Synthesis of phosphono-substituted porphyrin compounds for attachment to metal oxide surfaces

ABSTRACT

A method of making a phosphono-substituted dipyrromethane comprises reacting an aldehyde or acetal having at least one phosphono group substituted thereon with pyrrole to produce a phosphono-substituted dipyrromethane; and wherein the phosphono is selected from the group consisting of dialkyl phosphono, diaryl phosphono, and dialkylaryl phosphono. Additional methods, intermediates and products are also described.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to and is a divisional of U.S.patent application Ser. No. 10/698,255, filed Oct. 31, 2003, now issuedas U.S. Pat. No. 7,148,361, the disclosure of which is incorporated byreference herein in its entirety.

This invention was made with Government support under grant numberMDA972-01-C-0072 from DARPA. The Government has certain rights to thisinvention.

FIELD OF THE INVENTION

The present invention concerns methods for the synthesis of porphyriniccompounds, and intermediates thereof, which compounds are useful forattachment to metal oxide surfaces for the production of solar cells andmolecular memory devices.

BACKGROUND OF THE INVENTION

We recently described a new design for a molecular-based memory devicewherein a layer of redox-active molecules is tethered to an ultra-thindielectric surface, which in turn is deposited on a semiconductor. ¹ Thedielectric layer and the molecular tether (linker and surface attachmentgroup) both provide barriers to electron transfer between thesemiconductor and the redox-active molecule. In this type ofmolecular-based field effect transistor, the charge stored in themolecules can change the current level in the transistor, therebyaffording a non-destructive means by which the charge state of themolecules can be detected.

In contrast with conventional semiconductor-based devices, the use ofcharge-storage molecules exploits the power of synthetic design totailor molecules that operate at low voltage and that provide multiplecharged states. Great latitude also exists in the design of the barrierspresented by both the tether and the dielectric layer. The barrierpresented by the tether can be tuned via synthetic organic chemistrywhile that of the dielectric can be tuned by semiconductor-processingtechniques. In particular, the composition (and length) of the tethercan be varied from insulating aliphatic groups to more conductingconjugating species. Likewise, composition of the dielectric layer canbe a commonly used SiO₂ layer or a metal oxide such as HfO₂, ZrO₂, etc.

Our preliminary studies employed ferrocenylmethylphosphonic acid as thecharge-storage molecule.¹ The phosphonic acid group anchors thecharge-storage molecule to the oxide surface. The initial success ofthis approach has prompted us to investigate the synthesis of a muchwider variety of charge-storage molecules, particularly porphyrinicmolecules, which bear phosphonic acid-terminated linkers. Porphyrinsbearing phosphonic acid tethers have been synthesized and attached tooxide surfaces for a variety of other applications including solarenergy, oxidative catalysis, sensing, and recognition ofpolysaccharides.²-¹⁴

The synthetic approaches that have been employed to prepare porphyrinsbearing phosphonic acid/phosphonate units can be characterized by (1)whether the phosphonate unit is introduced into precursors to theporphyrin or by derivatization of a preexisting porphyrin, (2) whetherstatistical or rational routes are employed, (3) the number and patternof phosphonate groups at the perimeter of the porphyrin, (4) the type ofphosphonic acid protecting group employed, (5) the nature of the centralmetal, and (6) the method of cleavage of the phosphonate protectinggroups.

A₄-Porphyrins bearing four arylphosphonic acids have been prepared bycondensation of a dialkoxyphosphorylbenzaldehyde with pyrrole followedby deprotection of the free base porphyrin.² Alternatively, the freebase porphyrin can be metalated followed by deprotection.^(4,5)A₄-porphyrins bearing four alkylphosphonic acids have been prepared byderivatization of a reactive halo-substituted porphyrin.^(5,7)A₃B-porphyrins bearing a single phosphonic acid have been prepared by amixed-aldehyde condensation of a dialkoxyphosphorylbenzaldehyde,benzaldehyde, and pyrrole;⁴ or by derivatization of a porphyrin bearinga single reactive halo group.^(6,14) Trans-A₂B₂-porphyrins bearing twophosphonic acid groups have been prepared by condensation of adialkoxyphosphorylbenzaldehyde and dipyrromethane.¹² Chlorins bearingtwo phosphonic acids have been prepared by derivatization of adeuterochlorin-dibromide with tris(trimethylsilyl)phosphite.⁹ In eachcase, the porphyrinic species were employed as the free base or as ametal chelate that is rather robust toward the acidic conditions forcleavage of the dialkyl phosphonate. The metals include Mn,^(4,5) Fe,⁹Co,⁹ Ni,⁹ Pd,⁶ and Os,⁷ which are all categorized in the porphyrin fieldas class I or class II metals, affording chelates that are exceptionallyresilient toward acids.¹⁵ In general, phosphonic acids combine withmetals to give extended, often insoluble, metal phosphonates. A rarecase wherein metalation was performed in the presence of a freephosphonic acid employed a porphyrin superstructure containing ahindered phosphonic acid.¹⁴

One of the considerable attractions of molecular information storage isthe ability to tune the properties of the charge-storage moleculesthrough molecular design. In studies of thiol-derivatized porphyrins, wefound that the period during which the oxidized molecules remainedcharged (i.e., the charge-retention time) depends quite sensitively onthe length of the tether (linker and surface attachment group). Forexample, as the number of methylene groups in the tetherphenyl-(CH₂)_(n)—S— increased along the series 0, 1, 2, and 3, thecharge-retention time increased from 116, 167, 656 to 885 s. The rate ofelectron-transfer (reading process) also slowed with increase of linkerlength. Moreover, the quality (uniformity, integrity) of theself-assembled monolayers (SAMs) increased in going from the phenylthiotether (n=0) to the phenylalkylthio tethers (n=1-3).¹⁶

SUMMARY OF THE INVENTION

A first aspect of the invention is a method of making aphosphono-substituted dipyrromethane, comprising: reacting an aldehydeor acetal having at least one phosphono group substituted thereon withpyrrole to produce a phosphono-substituted dipyrromethane; and whereinthe phosphono is selected from the group consisting of dialkylphosphono, diaryl phosphono, and dialkylaryl phosphono. In someembodiments the aldehyde or acetal is coupled to the at least onephosphono by a linking group (e.g., aryl, alkyl, alkylaryl, andalkylarylalkyl linking groups). In some embodiments the aldehyde oracetal has three phosphono groups substituted thereon.

A second aspect of the present invention is a method of making aphosphono substituted dipyrromethane, comprising: reacting ahalo-substituted dipyrromethane with a phosphite to produce aphosphono-substituted dipyrromethane. The phosphite is generally adialkyl phosphite, diaryl phosphite, or dialkylaryl phosphite, and thephosphono is generally a dialkyl phosphono, diaryl phosphono, ordialkylaryl phosphono. In some embodiments, the halo is coupled to thedipyrromethane by a linking group such as described above.

A third aspect of the present invention is a 5-phosphonodipyrromethane,wherein the phosphono is selected from the group consisting of dialkylphosphono, diaryl phosphono, and dialkylaryl phosphono. In someembodiments the phosphono is coupled to the dipyrromethane by a linkinggroup such as described above.

A fourth aspect of the present invention is a method of making a5-phosphono, 1-acyldipyrromethane, comprising: reacting a5-phosphonodipyrromethane with a Grignard reagent to produce anintermediate compound; and then reacting the intermediate compound witha Mukaiyama reagent to produce a 5-phosphono, 1-acyldipyrromethane. Insome embodiments the 5-phosphono is selected from the group consistingof dialkyl phosphono, diaryl phosphono, and dialkylaryl phosphono and insome embodiments the phosphono is coupled to the dipyrromethane by alinking group such as described herein.

A fifth aspect of the present invention is a dipyrromethane selectedfrom the group consisting of (a) 1-phosphonoacyldipyrromethanes, and (b)5-phosphono, 1-acyldipyrromethanes. In some embodiments the 5-phosphonois dialkyl phosphono, diaryl phosphono, or dialkylaryl phosphono. Wherethe compound is a 5-phosphono, 1-acyldipyrromethane, the 1-acyl groupmay be a 1-phosphonoacyl group to provide a compound having twophosphono groups thereon.

A sixth aspect of the present invention is a method of making a 9-halo,5-phosphono, 1-acyldipyrromethane, comprising: halogenating a5-phosphono, 1-acyldipyrromethane to produce a 9-halo, 5-phosphono,1-acyldipyrromethan; wherein the phosphono is selected from the groupconsisting of dialkyl phosphono, diaryl phosphono, and dialkylarylphosphono. The phosphono may be coupled to the dipyrromethane by alinking group such as described herein.

A seventh aspect of the invention is a 9-halo, 5-phosphono,1-acyldipyrromethane compound. The phosphono is preferably dialkylphosphono, diaryl phosphono, or dialkylaryl phosphono. The phosphono maybe coupled to the dipyrromethane by a linking group such as describedherein.

An eighth aspect of the invention is a method of making a chlorin,comprising: reducing a 9-halo, 5-phosphono, 1-acyldipyrromethane toproduce a first reaction product; and then reacting the first reactionproduct with a western half to produce the chlorin; wherein thephosphono is selected from the group consisting of dialkyl phosphono,diaryl phosphono, and dialkylaryl phosphono. The phosphono may becoupled to the dipyrromethane by a linking group such as describedherein.

A ninth aspect of the present invention is a chlorin having a phosphonogroup coupled thereto at the 5 position, the 10 position, or both the 5and 10 position. In some embodiments the phosphono may be dialkylphosphono, diaryl phosphono, or dialkylaryl phosphono, and the phosphonomay be coupled to the chlorin by a linking group such as describedherein.

A tenth aspect of the invention is a method of making a porphyrinsubstituted at the 5 position with at least one phosphono group,comprising: reacting a 5-phosphono-substituted dipyrromethane with adipyrromethane-dicarbinol to produce the porphyrin; wherein thephosphono is selected from the group consisting of dialkyl phosphono,diaryl phosphono, and dialkylaryl phosphono. In some embodiments thephosphono is coupled to the dipyrromethane by a linking group such asdescribed herein. In some embodiments the at least one phosphono groupconsists of three phosphono groups.

An eleventh aspect of the invention is a porphyrin substituted at boththe 5 position and the 10 position with a phosphono group, such asdescribed herein.

A twelfth aspect of the invention is a method of making a substitutedporphyrin compound, comprising: reacting a halo-substituted porphyrinwith a phosphite or a salt thereof to produce a porphyrin having aphosphono group coupled thereto; wherein the phosphite is selected fromthe group consisting of dialkyl phosphite, diaryl phosphite, dialkylarylphosphite, trialkyl phosphite, triaryl phosphite, and trialkylarylphosphite; and wherein the phosphono is selected from the groupconsisting of dialkyl phosphono, diaryl phosphono, and dialkylarylphosphono. In some embodiments the halo-substituted porphyrin comprisesa porphyrin having a halo group coupled thereto by an intermediatelinking group such as described herein. The method may further comprisethe step of metalating the porphyrin having a phosphono group coupledthereto.

A thirteenth aspect of the invention is a method of making aphosphono-substituted porphyrin or chlorin, comprising: reacting aporphyrin or chlorin having a protected phosphono group substitutedthereon at the 5 position with a trialkysily halide and a base in asolvent to produce a porphyrin or chlorin having a phosphonic acid groupsubstituted thereon. In some embodiments the phosphono is coupled to theporphyrin or chlorin with an intermediate linking group such asdescribed herein.

A fourteenth aspect of the invention is a method of making coupledporphyrins, comprising: reacting (i) a first porphyrin substituted witha halo or ethyne group and a protected phosphono group with (ii) asecond porphyrin having an ethyne or halo group in a Sonogashirareaction to couple the first and second porphyrins; wherein the firstporphyrin is substituted with halo when the second porphyrin issubstituted with ethyne, and the first porphyrin is substituted withethyne when the second porphyrin is substituted with halo.

The foregoing and other objects and aspects of the present invention areexplained in greater detail in the specification set forth below.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

“Alkyl,” as used herein, refers to a straight or branched chainhydrocarbon, for example containing from 1 to 10 or 20 carbon atoms.Representative examples of alkyl include, but are not limited to,methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl,tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, 3-methylhexyl,2,2-dimethylpentyl, 2,3-dimethylpentyl, n-heptyl, n-octyl, n-nonyl,n-decyl, and the like. When used as a linking group alkyl as describedherein includes two covalent bonds, one to each linked group.

“Aryl,” as used herein, refers to a monocyclic carbocyclic ring systemor a bicyclic carbocyclic fused ring system having one or more aromaticrings. Representative examples of aryl include azulenyl, indanyl,indenyl, naphthyl, phenyl, tetrahydronaphthyl, and the like. When usedas a linking group alkyl as described herein includes two covalentbonds, one to each linked group.

“Phosphono” as used herein refers to unprotected phosphono groups of theformula —R—P(═O)(OH)₂, where R is a linking group or a covalent linkage,as well as protected phosphono groups of the formula —R—P(═O)(OR¹)₂,where R is a linking group or a covalent bond and R¹ is alkyl, aryl, oralkylaryl.

“Acyl” as used herein means a —C(═O)R group, where R is a suitablesubstituent such as alkyl, aryl, or alkylaryl, which substituent may besubstituted or unsubstituted.

“Phosphonoacyl” as used herein means a group of the formula —C(═O)R,where R is a phosphono group as described above.

“Dialkylaryl phosphono” as used herein refers to a compound of theformula —P(═O)(OR¹R²)₂ where R¹ is alkyl and R² is aryl. Likewise“trialkylaryl” refers to the presence of three substitutents of theformula —R¹R² on the indicated group (where R¹ is alkyl and R² is aryl).

“Halo” as used herein refers to halogens such as chloro, bromo or iodo.

“Linking group” as used herein refers to any suitable group having twocovalent bonds, one to each linked group, such as alkyl, aryl,alkylaryl, or alkylarylalkyl linking groups. Additional covalent bondsare included when additional groups are linked.

“Porphyrin” as used herein refers to substituted or unsubstitutedporphyrins and includes porphyrins with extra rings ortho-fused, orortho-perifused, to the porphyrin nucleus, porphyrins having areplacement of one or more carbon atoms of the porphyrin ring by an atomof another element (skeletal replacement), derivatives having areplacement of a nitrogen atom of the porphyrin ring by an atom ofanother element (skeletal replacement of nitrogen), derivatives havingsubstituents other than hydrogen located at the peripheral (meso-,beta-) or core atoms of the porphyrin, porphyrins with saturation of oneor more bonds of the porphyrin (hydroporphyrins, e.g., chlorins,bacteriochlorins, isobacteriochlorins, decahydroporphyrins, corphins,pyrrocorphins, etc.), porphyrins obtained by coordination of one or moremetals to one or more porphyrin atoms (metalloporphyrins), porphyrinshaving one or more atoms, including pyrrolic and pyrromethenyl units,inserted in the porphyrin ring (expanded porphyrins), porphyrins havingone or more groups removed from the porphyrin ring (contractedporphyrins, e.g., corrin, corrole) and combinations of the foregoingderivatives (e.g. phthalocyanines, subphthalocyanines, and porphyrinisomers). Preferred porphyrins comprise at least one 5-membered ring andmore preferably include four 5-membered rings, each of which includes ahetero atom such as N, S, or O, preferably N in a position for formationof a coordination bond.

“Grignard reagent” and “Mukaiyama reagent” are as described in furtherdetail below.

“Eastern half” and “Western half” are as described in further detailbelow.

The disclosures of all United States patent references cited herein areto be incorporated by reference herein in their entirety.

The present invention provides methods of making a phosphono-substituteddipyrromethane. In general, such methods comprise reacting an aldehydeor acetal having at least one phosphono group substituted thereon withpyrrole to produce a phosphono-substituted dipyrromethane, with thedipyrromethane preferably substituted by the phosphono group at the 5position thereof (see for example Scheme 4 below). In general, thephosphono group may be a dialkyl phosphono, diaryl phosphono, ordialkylaryl phosphono group. The aldehyde or acetal may be coupled tothe at least one dialkyl phosphono by a linking group. In someembodiments, the aldehyde or acetal has three phosphono groupssubstituted thereon (e.g., by coupling to dipyrromethane at the 5position a group of the formula —R¹(R²Z)₃, where R¹ is a first linkinggroup, R² is a second linking group, and Z is a phosphono group). Suchreactions are generally carried out with an acid catalyst, or without anacid catalyst in the presence of heat. Depending upon whether or not acatalyst is used, the reactions are carried out at an elevatedtemperature of up to about 100° C., and more typically at a temperatureof 50 to 100° C. Any suitable acid catalyst may be used, includingindium trichloride, scandium triflate, TFA, BF₃ etherate, etc. While thepyrrole serves as the solvent a cosolvent or diluent may optionally beincluded, examples of which include but are not limited to toluene,methylene chloride, chloroform, etc.

Another method of making a phosphono substituted dipyrromethanedescribed herein comprises reacting a halo-substituted dipyrromethanewith a phosphite to produce a phosphono-substituted dipyrromethane (seefor example Scheme 4 below). In general, the phosphite is a dialkylphosphite, a diaryl phosphite, or a dialkylaryl phosphite, and thecorresponding phosphono is a dialkyl phosphono, a diaryl phosphono, or adialkylaryl phosphono. The halo is preferably coupled to thedipyyromethane at the 5 position, and may be coupled to thedipyrromethane by a linking group. Where the linking group is orincludes an aryl to which the halo is coupled, the halo may be coupledto the aryl at the ortho, meta or para position. In general, suchreactions are catalyzed with a metal such as palladium or nickel and arecarried out in a suitable solvent such as toluene or triethylamine, andare carried out at any suitable temperature such as 50 to 150° C. (e.g.,under reflux) for any suitable time, such as 1-24 hours (e.g.,overnight). An alternative, when the dipyrromethane is substituted witha haloalkyl, is to treat the dipyrromethane with a trialkylphosphite ortriarylphosphite at a temperature of 0 or 50 to 150° C. (salts can bereacted at room temperature).

The present invention further provides a method of making a 5-phosphono,1-acyldipyrromethane. In general, the method comprises reacting a5-phosphonodipyrromethane with a Grignard reagent to produce anintermediate compound, and then reacting the intermediate compound witha Mukaiyama reagent to produce a 5-phosphono, I-acyldipyrromethane (seefor example Scheme 6 herein). The 5-phosphonodipyrromethane can be asdescribed herein and produced by methods such as described above. Thereaction can be carried out in accordance with techniques known to thoseskilled in the art (see, e.g., U.S. Pat. Nos. 6,617,282, 6,608,212,6,603,000 and 6,600,040, describing Grignard reagents).

Alternatively, the phosphono group can be introduced at the 1-positionof the dipyrromethane in an acylation reaction between a dipyrromethaneand a Mukaiyama reagent bearing the phosphono functional group. TheMukaiyama reagent is, in general, any suitable Mukaiyama reagent,typically a 2-S-pyridyl phosphono thioate, where phosphono may beprotected or unprotected as described herein and may include a linkinggroup as described herein. The reaction may be carried out in anysuitable solvent, such as an ethereal solvent such as THF, and ispreferably carried out under chilled conditions. In this manner,monoacyl dipyrromethanes bearing a phosphono group at the 1-, 5-, or 1-and 5-positions of the dipyrromethane can be prepared, by inclusion ofthe phosphono group on the acyl group.

A method of making a 9-halo, 5-phosphono, 1-acyldipyrromethane is alsodescribed herein. The method comprises halogenating a 5-phosphono,1-acyldipyrromethane to produce a 9-halo, 5-phosphono,1-acyldipyrromethane (see for example Scheme 8 below). In general, thephosphono group may be a dialkyl phosphono, diaryl phosphono, ordialkylaryl phosphono group (which may be coupled to the 5 position by alinking group as described above), and the halo may be chloro, bromo oriodo, preferably bromo. Any halogenating agent may be used, includingbut not limited to N-chlorosuccinimide, N-bromosuccinimide,N-iodosuccinimide, 1,3-dichloro-5,5-dimethylhydantoin,1,3-dibromo-5,5-dimethylhydantoin, chlorine, bromine, and iodine. Thereaction is preferably carried out at a temperature less than roomtemperature, most preferably 0 to −100° C., in any suitable solvent suchas tetrahydrofuran, dioxane, diethyl ether or other ethereal solvents,but preferably THF.

A method of making a chlorin is also described herein. The methodcomprises reducing a 9-halo, 5-phosphono, 1-acyldipyrromethane toproduce a first reaction product (an “Eastern half”); and then reactingthe first reaction product eastern half with a Western half to producethe chlorin (see for example Scheme 8 below). The 9-halo, 5-phosphono,1-acyldipyyromethane may be produced as described above, and in general,the phosphono may be dialkyl phosphono, diaryl phosphono, or dialkylarylphosphono. The terms “Eastern half” and “Western half” are known in theart of chlorin chemistry; reactions for producing a chlorin from easternand western halves are known in the art of chlorin chemistry, and can becarried out in accordance with known techniques or variations thereofwhich will be apparent to those skilled in the art given the presentdisclosure. See, e.g., U.S. Pat. No. 6,559,374 to Lindsey andBalasubramanian.

A method of making a porphyrin substituted at the 5 position with atleast one phosphono group is also described herein. The method comprisesreacting a 5-phosphono-substituted dipyrromethane with adipyrromethane-dicarbinol to produce the porphyrin (see for exampleScheme 5 below). In general, the phosphono may be a dialkyl phosphono,diaryl phosphono, or dialkylaryl phosphono, and in general the phosphonomay be coupled to the dipyrromethane by a linking group as describedabove. In some embodiments the at least one phosphono group consists ofthree phosphono groups (e.g., by coupling to the dipyrromethane at the 5position a group of the formula —R¹(R²Z)₃, where R¹ is a first linkinggroup, R² is a second linking group, and Z is a phosphono group). Themethods may be carried out in accordance with known techniques, such asdescribed in U.S. patent application No. 2003/0096978 A1 (published May22, 2003) to Lindsey, Geier and Yu. In general, the reactions may becarried out at any suitable temperature and pressure, such as roomtemperature and ambient pressure. In general the reactions are carriedout within a time of 1 to 2 hours. Solvents which may be used to carryout the present invention preferably have a dielectric constant of about20, 15, or 10 or less, at room temperature (i.e., 25° C.). The solventmay be a single compound or mixtures thereof. Preferably the solvent isnon-aqueous. Particular examples of suitable solvents include, but arenot limited to, chlorinated aliphatic hydrocarbons (e.g.,dichloromethane, chloroform, 1,2-dichloroethane, 1,1,1,-trichloroethane,1,1,2,2-tetrachloroethane, 1,1-dichloroethylene,cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, trichloroethylene,etc.); chlorinated aromatic hydrocarbons (e.g., chlorobenzene,1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene,1-chloronaphthalene, etc.); hydrocarbons (e.g., benzene, toluene,xylene, ethylbenzene, mesitylene, durene, naphthalene); ethers (e.g.,ethyl ether, propyl ether, tetrahydrofaran, p-dioxane, anisole, phenylether, etc.); esters (e.g., ethyl acetate, methyl acetate, ethylbenzoate, butyl phthalate, etc.); glymes (e.g., 2-methoxyethanol,2-butoxyethanol), and other solvents such as carbon disulfide, tributylborate, etc., and mixtures of the foregoing. Any suitable electron-pairacceptor may be used as the Lewis acid catalyst in the presentinvention, including, but not limited to, CsCl, SmCl₃.6H₂O, InCl₃, CrF₃,AlF₃, Sc(OTf)₃, TiF₄, BEt₃, GeI₄, EuCl₃.nH₂O, LaCl₃, Ln(OTf)₃ where Ln=alanthanide, etc. The concentration of the Lewis acid may range, forexample, from 0.001 or 0.01 mmol/L to 100 or 500 mmol/L, or more.

The preparation of a porphyrin bearing two dialkyl phosphono diarylphosphono, or dialkylaryl phosphono groups at the 5- and 10-positions(cis-A₂B₂ or cis-A₂BC type porphyrins) can be prepared by condensationof a dipyrromethane-dicarbinol bearing two dialkyl phosphono, diarylphosphono, or dialkylaryl phosphono groups at the 1- and 5-positionswith a dipyrromethane.

Reactions of Porphyrins. The present invention also provides forreactions of porphyrins. Among other things the present inventionprovides a method of making a substituted porphyrin compound,comprising: reacting a halo-substituted porphyrin with a phosphite, or asalt thereof, to produce a porphyrin having a phosphono group coupledthereto (see for example Scheme 11). In general the phosphite may be adialkyl phosphite, diaryl phosphite, dialkylaryl phosphite, trialkylphosphite, triaryl phosphite, or trialkylaryl phosphite, and thecorresponding phosphono may be a dialkyl phosphono, diaryl phosphono, ordialkylaryl phosphono. The halo group may be coupled to the porphyrin byan intermediate linking group as described above. In some embodiments,the porphyrin on which the reaction is performed may be a member of adouble-decker or triple-decker sandwich coordination compound. Reactionsmay be carried out in the same manner as described in connection withphosphites above, and may further comprise the step of metalating theporphyrin in accordance with known techniques.

A method of making a phosphonic acid-substituted porphyrin or chlorin isalso described herein. The method generally comprises reacting aporphyrin or chlorin having a protected phosphono group substitutedthereon at the 5 position with a trialkyl silylhalide and a base in asolvent to produce a porphyrin or chlorin having a phosphonic acid groupsubstituted thereon (see for example Scheme 10 below). The phosphono maybe coupled to the porphyrin or chlorin with an intermediate linkinggroup such as described above. When porphyrins are used, the porphyrinmay be a member of a double-decker or triple-decker sandwichcoordination compound. Any suitable trialkylsilyl halide may be used,including but not limited to trimethylsilyl chloride and trimethylsilylbromide. The base is preferably a tertiary amine, more preferably atrialkylamine and most preferably triethylamine. The reaction may becarried out in any suitable solvent such as CH₂Cl₂, CHCl₃,chlorobenzene, etc. at any suitable temperature (e.g., 0 to 200° C.) forany suitable time (e.g., 1 to 24 hours) and may conveniently be carriedout under reflux in CHCl₃.

The present invention farther provides a method of making coupledporphyrins, comprising: reacting (i) a first porphyrin substituted witha halo or ethyne group and a protected phosphono group with (ii) asecond porphyrin having an ethyne or halo group in a Sonogashirareaction to couple said first and second porphyrins, wherein said firstporphyrin is substituted with halo when said second porphyrin issubstituted with ethyne, and said first porphyrin is substituted withethyne when said second porphyrin is substituted with halo (see forexample Scheme 9 below). As previously, in some embodiments one or bothof the first and second porphyrins may comprise a member of adouble-decker or triple-decker sandwich coordination compound. Suchreactions may be carried out in accordance with known techniques,including but not limited to those described in U.S. Pat. No. 6,603,070to Lindsey and Loewe.

Compounds of the present invention (including the products of theprocesses described herein) are useful, among other things, for theproduction of polymers thereof which may be immobilized or coupled to asubstrate and used as light harvesting rods, light harvesting arrays,and solar cells, as described for example in U.S. Pat. No. 6,407,330 toLindsey et al. or U.S. Pat. No. 6,420,648 to Lindsey. Compounds of thepresent invention are also useful immobilized to a substrate for makingcharge storage molecules and information storage devices containing thesame. Such charge storage molecules and information storage devices areknown and described in, for example, U.S. Pat. No. 6,208,553 to Gryko etal.; U.S. Pat. No. 6,381,169 to Bocian et al.; and U.S. Pat. No.6,324,091 to Gryko et al. The compounds of the invention, particularlyporphyrins, and including products and intermediates, may comprise amember of a double-decker or triple-decker sandwich coordinationcompound, such as for use as an information storage molecule, such asdescribed in U.S. Pat. No. 6,212,093 to Li et al. or U.S. Pat. No.6,451,942 to Li et al.

The present invention is explained in greater detail in the non-limitingExamples set forth below.

EXPERIMENTAL

Example I below shows that synthetic molecules bearing phosphonic acidgroups can be readily attached to oxide surfaces. As part of a programin molecular-based information storage, we have developed routes for thesynthesis of diverse porphyrinic compounds bearing phenylphosphonic acidtethers. The routes enable (1) incorporation of masked phosphonic acidgroups in precursors for use in the rational synthesis of porphyriniccompounds, and (2) derivatization of porphyrins with masked phosphonicacid groups. The precursors include dipyrromethanes,acyldipyrromethanes, and diacyldipyrromethanes. The tert-butyl group hasbeen used to mask the dihydroxyphosphoryl substituent. Thedi-tert-butyloxyphosphoryl unit is stable to the range of conditionsemployed in syntheses of porphyrins and multiporphyrin arrays, yet canbe deprotected under mild conditions (TMS-Cl/TEA or TMS-Br/TEA inrefluxing CHCl₃) that do not cause demetalation of zinc porphyrins(class III) or magnesium porphyrins (class IV). The porphyriniccompounds that have been prepared include (1) A₃B-, trans-AB₂C-, andABCD-porphyrins that bear a single phenylphosphonic acid group, (2) atrans-A₂B₂-porphyrin bearing two phenylphosphonic acid groups, (3) achlorin that bears a single phenylphosphonic acid group, and (4) aporphyrin dyad bearing a single phenylphosphonic acid group.

In Example II below we describe the synthesis of porphyrins bearingbenzylphosphonic acid, hexylphosphonic acid, and tripodal phosphonicacid tethers. The benzyl and hexyl linkers are longer than a phenyl unitwhile the tripodal tether anchors the redox-active molecule in a 3-pointcontact and enforces a vertical orientation of the charge-storagemolecule. The key design issues for tripods are (1) the nature of theatom or molecular unit to which the three legs of the tripod areattached, (2) the composition and length of the tripod legs, and (3) thenature of the three terminal groups for surface attachment. Diversetripodal tethers have been prepared for attaching molecules to surfaces.Tripods containing a C atom,¹⁷⁻³⁰ a Si atom,³¹ or anadamantane^(26,32-35) unit at the central core of the tripod have beenprepared. The tripod legs include methyl,^(22,34) ethyl,²¹propyl,^(17,19,20,22,23) alkyl ether,¹⁸ phenyl^(26,32,33)benzyl,^(24,25,27,30) biphenyl,^(28,29) diphenylethyne,^(31,35) andoligoethynylphenyl³⁵ structures. The terminal groups includethiol,^(17,19,20,22,24,25,27,30,34) S-acetylthio,^(23,25,27,31,35)thiocyanate,²² alcohol,^(22,34) ester,^(18,26,32,33,34) carboxylicacid,^(18,21,26,33) diethyl phosphonate,²⁸ or phosphonic acid^(28,29)groups. Some of the tripods bear redox-active groups includingferrocene,^(21,22) viologen,^(28,29) fullerene,^(18,25,27)ruthenium-tris(bpy),^(26,32) or oligothiophene^(25,27,30) units.Dendrimeric tripods bearing more than three sites of attachment alsohave been prepared.^(17,18,21,36)

A tripod built around a tetraarylmethane structure containing threeterminal phosphonic acid groups appeared most attractive for ourpurposes owing to the rigid, compact, and tetrahedral architecture. Thetripods of this type that have been prepared incorporatemethylthiol^(24,25,27,30) or ester^(26,32) termini attached to phenyllegs, or dialkyl phosphono termini attached to biphenyl legs.^(28,29)The synthesis of the thiolterminated tetraarylmethane tripod proceededthrough the valuable intermediate1,1,1-tris(4-bromomethylphenyl)(4-bromophenyl)methane.²⁷ We felt thatthe route for preparing this intermediate could be adapted toincorporate porphyrins and benzylphosphonic acid groups.

EXAMPLE I

1. Approach. A variety of protecting groups have been used forphosphonic acids, including methyl, ethyl, allyl, and tert-butylgroups.^(2-14,37-43) For our application, a key issue concerns thestability of the metalloporphyrin towards conditions employed forprotecting group removal, as inadvertent demetalation of the porphyrinwould complicate the synthesis of mixed-metal multiporphyrin arrays.Accordingly, the ideal masking agent should meet the followingrequirements: (1) Compatibility with porphyrin forming conditions,including acid catalysis and DDQ oxidation conditions. (2) Stabilitytowards a variety of metalation conditions. (3) Compatibility withPd-mediated coupling reactions. (4) Undergo cleavage withoutdemetalation of the metalloporphyrins.

Mild conditions for the cleavage of a dialkyl phosphonate to give thephosphonic acid originate with Rabinowitz, who first used trimethylsilylchloride (TMS-Cl) followed by hydrolysis of the resultingbis(trimethylsilyl) phosphonate.⁴⁴ Modifications of this approach haveled to the following conditions: (1) TMS-Br (neat);³⁷ (2) TMS-Br/CH₃CN⁴²or CH₂Cl₂;⁴⁰ (3) TMS-Cl/TEA;⁴⁵ and (4) TMS-Br/TEA/CH₂Cl₂.⁴¹ Some ofthese approaches have been applied to the cleavage of a diethylporphyrin-phosphonate: (1) TMS-Br/CH₂Cl₂ (free baseporphyrins);^(6,7,12) (2) TMS-Br/TEA/DMF (Mn-porphyrin);¹³ and (3)NaBr/TMS-Cl/TEA/DW (Mn-porphyrin).⁴

We have examined methods for the introduction and cleavage of variousphosphonic acid protecting groups that are compatible with thepreparation of diverse porphyrinic compounds. Several possible maskingagents [2-trimethylsilylethyl, 2-cyanoethyl, 2-chloroethyl, methyl] wereexamined but found inapplicable for the preparation ofporphyrin-phosphonic acids. The tert-butyl group has been used for theprotection of phosphates in nucleotide syntheses with facile removalunder mild non-acidic conditions (TMS-Cl/TEA).⁴⁵ We therefore employedthe tert-butyl group as masking agent in the work described herein.

2. Synthesis. A sample of 4-bromobenzaldehyde dimethylacetal⁴⁶ wascoupled with di-tert-butylphosphite to give4-(di-tert-butyloxyphosphoryl)benzaldehyde dimethylacetal. The latterwas used in a mixed-aldehyde condensation⁴⁷ with pyrrole under standardconditions of BF₃.O(Et)₂-ethanol cocatalysis⁴⁸ followed by oxidationwith DDQ to give porphyrin 1. Porphyrin 1 was metalated withZn(OAc)₂.2H₂O in CHCl₃/methanol to afford zinc porphyrin Zn1 in 73%yield (Scheme 1). Cleavage of the tert-butyl groups was achieved byfollowing the known procedure⁴⁵ with TMS-Cl/TEA in refluxing CHCl₃(stabilized with amylenes). In this manner, the porphyrin Zn2 wasobtained without demetalation in 89% yield. Note that CHCl₃ stabilizedwith amylenes rather than ethanol was used to avoid the possiblereaction of ethanol with TMS-Cl.

The synthesis of magnesium porphyrin Mg1 was first tried using theheterogeneous magnesium insertion procedure.⁴⁹ Porphyrin 1 was treatedwith MgI₂ and DIEA in CH₂Cl₂ at room temperature, but these conditionsresulted in cleavage of the tert-butyl groups. However, magnesiuminsertion using the homogeneous procedure⁵⁰ (ethereal MgI₂-DIEA reagentin CH2Cl₂) gave Mg1 in 71% yield. Treatment of Mg1 with TMS-Cl/TEA inrefluxing CHCl₃ or THF did not cause cleavage of the tert-butyl groups.However, use of TMS-Br/TEA in refluxing CHCl₃ gave porphyrin-phosphonicacid Mg2 in 77% yield (Scheme 2).

We also examined the diethyl phosphono porphyrin Zn3, which was preparedfrom 4-(diethoxyphosphoryl)benzaldehyde⁴ in the same manner as for Zn1.We found that Zn3 could be deprotected in 81% yield without affectingthe metalation state by using the TMS-Br/TEA reagent in refluxing CHCl₃.On the other hand, treatment of Zn3 with TMS-Br in the absence of TEA(employed for the deprotection of diethyl phosphonates)⁶ at roomtemperature caused demetalation in addition to cleavage of the ethylgroups, affording the free base porphyrin-phosphonic acid 2 in 79% yield(Scheme 3). Porphyrin 2 was metalated with Zn(OAc)₂.2H₂O under standardconditions, giving Zn2 in 77% yield. The successful metalation of aporphyrin bearing a free phosphonic acid was surprising and may stem inpart from the suppression of aggregation afforded by the three mesitylgroups.

The success of the above studies prompted us to employ the di-tert-butylphosphono group in a variety of porphyrin precursors. Accordingly,reaction of acetal 4 with excess pyrrole following a standardprocedure⁵¹ afforded dipyrromethane 6 in 31% yield (Scheme 4).Alternatively, Pd-mediated coupling of 5-(4-bromophenyl)dipyrromethane(5)⁵¹ with di-tert-butylphosphite gave 6 in 43% yield. Dipyrromethane 6is a valuable synthon for use in porphyrin chemistry.

Dipyrromethane 6 was treated with various dipyrromethane-dicarbinols(7-diol, 8-diol, and 9-diol)⁵² in a rational route⁵² to afford thecorresponding porphyrins 10, 11, and 12 in 4.6%, 7.8% and 25% yieldsrespectively (Scheme 5). The synthesis of 10 was achieved using Yb(OTf)₃as acid catalysis⁵³ while that of 11 and 12 was carried out with TFA.

Scheme 5

Porphyrin Ar¹ Ar² Ar³ Diol (% yield)

7-diol 10 (4.6%)

8-diol 11 (7.8%)

9-diol 12 (25%)

Application of the procedure for monoacylation of a dipyrromethane⁵⁴ to6 by treatment with EtMgBr and pyridyl thioester 13⁵⁴ or 14⁵² gave thecorresponding monoacyl product 15 or 16 in 48% or 69% yield,respectively (Scheme 6).

Compound 15 on reduction with NaBH₄ in THF/methanol afforded themonocarbinol 15-OH. Self-condensation⁵⁴ of 15-OH on treatment with TFAin CH₃CN followed by oxidation with DDQ afforded thebis-phosphonate-porphyrin 17 in 28% yield (Scheme 7). Theself-condensation of 15-OH using InCl₃ as catalyst⁵³ resulted in a verylow yield (3%) of the required porphyrin 17.

A chlorin bearing a phenylphosphonic acid tether also was prepared.Monoacyl-dipyrromethane 15 was treated with NBS to afford 18 in 78%yield. Reduction of 18 with NaBH₄ gave the monocarbinol 18-OH (Easternhalf), which on reaction with tetrahydrodipyrrin 19⁵⁵ (Western half)under one-flask chlorin-forming conditions⁵⁵ gave thephosphonate-substituted zinc chlorin Zn20 in 17% yield (Scheme 8).Treatment of Zn20 with TMS-Cl/TEA in CHCl₃ at reflux afforded the zincchlorin-phosphonic acid Zn21 in 88% yield.

The synthesis of a porphyrin dyad bearing a single phosphonic acidtether is shown in Scheme 9. The synthesis employed Zn22⁵⁶ with Zn23;Zn23 was prepared by coupling ofZn(II)-5-(4-iodophenyl)-10,20-dimesityl-15-[4-[2-(trimethylsilyl)ethynyl]phenyl]porphyrin⁵⁷and di-tert-butyl phosphite. The Sonogashira coupling of Zn22 with Zn23was carried out under the conditions developed for synthesis ofmultiporphyrin arrays.⁵⁸ The conditions employ equimolar amounts of thetwo porphyrins in relatively dilute solution (5 mM each in toluene/TEA)at 35° C. with catalysis by Pd₂(dba)₃ and tri-o-tolylphosphine[P(o-tol)₃] without any copper cocatalysts. Thus, the coupling of Zn23with Zn22 afforded Dyad-1 in 54% yield upon chromatographic workupincluding size exclusion chromatography⁵⁹ (SEC). Treatment of the dyadwith TMS-Cl/TEA in refluxing CHCl₃ afforded Dyad-2 bearing a freephosphonic acid in 82% yield. No demetalation of the zinc porphyrins wasobserved.

3. Characterization. The porphyrins and chlorins were characterized byabsorption spectroscopy, ¹H NMR spectroscopy, LDMS⁶⁰ and FABMS. Thephosphonic acid/phosphonate-containing compounds were also characterizedby ³¹P NMR spectroscopy using H₃PO₄ as an external standard. The ³¹P NMRspectrum of each of the phosphonate-containing compounds yielded asinglet. The ¹H NMR and ¹³C NMR spectra of the molecules bearingphosphonate groups showed splitting of some signals originating fromatoms in the adjacent phenylene or alkyl phosphonate unit due tocoupling with the phosphorous nucleus. ¹H NMR and ³¹P NMR spectra forZn21 were not obtained (in CDCl₃, THF-d₈, CD₃OD, or DMSO-d₆) due toaggregation.

EXAMPLE II

The ability to attach redox-active molecules to oxide surfaces incontrolled architectures (distance, orientation, packing density) isessential for the design of a variety of molecular-based informationstorage devices. We describe the synthesis of a series of redox-activemolecules wherein each molecule bears a benzylphosphonic acid tether.The redox-active molecules include zinc porphyrins and acobalt(II)porphyrin. An analogous tripodal tether has been prepared thatis based on a tris-[4-(dihydroxyphosphorylmethyl)phenyl]-derivatizedmethane. A zinc porphyrin is linked to the methane vertex by a1,4-phenylene unit. The tripodal systems are designed to improvemonolayer stability and ensure vertical orientation of the redox-activeporphyrin on the electroactive surface. For comparison purposes, a zincporphyrin bearing a hexylphosphonic acid tether also has been prepared.The synthetic approaches for introduction of the phosphonic acid groupinclude derivatization of a bromoalkyl porphyrin or use of a dimethyl ordiethyl phosphonate-substituted precursor in a porphyrin-formingreaction. The latter approach makes use of dipyrromethane buildingblocks bearing mono or tripodal dialkyl phosphonate groups.Collectively, a variety of porphyrinic molecules can now be preparedwith tethers of different length, composition, and structure (mono ortripodal) for studies of molecular-based information storage on oxidesurfaces.

1. Synthesis. Zinc Porphyrins Bearing Single Tethers. (a)Benzylphosphonic Acid Tethers. Porphyrin 24 was treated withZn(OAc)₂.2H₂O to afford Zn24 in 94% yield (Scheme 10). Treatment of Zn24to the same conditions described in Example I to cleave di-tert-butylgroups [TMS-Br (15 equiv) and TEA (20 equiv) in refluxing CHCl₃] causedcleavage of the ethyl protecting groups to affordporphyrin-benzylphosphonic acid Zn25 in 78% yield.

Porphyrin 24 could also be prepared following the approaches shown inScheme 11. The mixed-aldehyde condensation⁴⁷ at high concentration⁶¹ of4-bromomethylbenzaldehyde,⁶² mesitaldehyde, and pyrrole withBF₃.O(Et)₂-ethanol cocatalysis⁴⁸ followed by oxidation with DDQ affordedthe porphyrin (26) that bears one bromomethyl group. Porphyrin 26 is avaluable porphyrin building block. As with otherbromomethylporphyrins,⁶³ 26 can be functionalized with a wide variety ofnucleophiles. For example, treatment of 26 with triethyl phosphite in anArbuzov reaction, or sodium diethyl phosphite in THF, gave porphyrin 24in 80% or 73% yield, respectively. Both routes afford porphyrin 24 in astraightforward manner. Porphyrin 26 could also be treated withtrimethyl phosphite in an Arbuzov reaction affording porphyrin 27 in 79%yield. Zinc insertion afforded porphyrin Zn27 in 98% yield. The methylgroups were cleaved under the same conditions employed for Zn24,affording porphyrin Zn25 in 77% yield. Based on this single comparison,the methyl and ethyl protecting groups seem comparable in affording thecorresponding porphyrin-phosphonic acid.

The synthesis of a porphyrin-phosphonic acid bearing p-tolyl groups atall non-linking meso positions is shown in Scheme 12. The synthesisrelies on the rational condensation of a dipyromethane and adipyrromethane-dicarbinol.⁵² Reaction of4-(diethoxyphosphorylmethyl)benzaldehyde (28) with excess pyrrole underTFA catalysis afforded dipyrromethane 29 in 46% yield. The condensationof 29 and 30-diol⁶⁴ in CH₂Cl₂ using InCl₃ as catalyst⁵³ followed byoxidation with DDQ afforded the free base porphyrin. The reaction ofcrude free base porphyrin with Zn(OAc)₂.2H₂O gave the zinc porphyrinZn31. However, the insolubility of Zn31 in typical solvents (CHCl₃, THF,toluene and mixtures thereof) prevented analysis. A suspension of Zn31in CH₂Cl₂ was treated with TFA, affording the free base porphyrin 31 in12% overall yield. Free base porphyrin 31 showed good solubility and wasreadily characterized.

(b) Hexylphosphonic Acid Tether. To explore the effect of tether lengthon the electron-transfer properties of porphyrin SAMs, we prepared aporphyrin that bears a hexylphosphonic acid tether (Scheme 13).Condensation of dipyrromethane 32⁶⁵ and 30-diol using InCl₃ followed byoxidation with DDQ afforded porphyrin 33 in 24% yield. Metalationfurnished Zn33 in 85% yield. An Arbuzov reaction of Zn33 andtriethylphosphite afforded porphyrin Zn34 in quantitative yield.Treatment with TMS-Br/TEA in refluxing CHCl₃ gaveporphyrin-hexylphosphonic acid Zn35 in 88% yield.

Porphyrin Architectures for Increased Memory Density. Molecules with anincreased number of cationic oxidation states can afford increasedmemory density. We have explored the use of cobalt(II)porphyrins toserve as molecules that can provide three cationic oxidation states: themono- and dication porphyrin radicals and a metal-centeredCo(II)/Co(III)⁶⁶ oxidation. The synthesis of a cobaltporphyrin-phosphonic acid is shown in Scheme 14. Porphyrin 24 wastreated with Co(OAc)₂ to yield the cobalt porphyrin Co24 in 68% yield.Cleavage of the ethyl protecting groups using the same proceduredescribed above (TMS-Br/TEA in refluxing CHCl₃) furnished theporphyrin-phosphonic acid Co25 in 92% yield.

Porphyrins Bearing Tripodal Phosphonic Acid Tethers. Our design forporphyrins bearing tripodal phosphonic acid tethers incorporates ap-phenylene group between the porphyrin and the methane-carbon vertex ofthe tripod. The three legs of the tripod are provided bybenzylphosphonic acid groups. The synthesis we developed proceeds via adipyrromethane bearing the tripod with protected phosphonic acid groups(Scheme 15).

The synthesis begins with 1-(4-bromophenyl)-1,1,1-tri-p-tolylmethane(36).²⁷ Rosenmund-von Braun reaction of 36 with CuCN afforded 37 in 60%yield (76% based on recovery of starting material 36). Radicalbromination of 37 using NBS (1.1 eq per methyl group) and AIBN inrefluxing benzene furnished crude tribromo nitrile 38 in ˜90% purity. ¹HNMR spectroscopy showed the presence of unreacted p-tolyl resonances,indicating incomplete bromination. The mono and dibromo products werenot easily removed from the reaction mixture; thus, the crude materialwas carried forward. Reduction of crude 38 with DIBALH gave aldehyde 39,which was 15 converted to the acetal (40) using TiCl₄ inCH₂Cl₂/methanol. Subsequent reaction with triethylphosphite at 100° C.for 6 h afforded 41 in 54% yield (from 37). The acetal was cleavedduring the acidic workup that was employed to convert the odoroustriethylphosphite to diethylphosphite. While each member of the seriesof compounds 38-40 was ˜90% pure owing to the presence of partiallybrominated species, 41 was obtained in pure form. Condensation of 41with excess pyrrole under new reaction conditions (InCl₃ as catalyst)⁶⁷afforded dipyrromethane 42 in 77% yield.

Dipyrromethane 42 serves as a valuable synthetic intermediate forcondensation with dipyrromethane-dicarbinols⁵² to afford porphyrinsbearing a tripodal phosphonate tether. Thus, condensation of 42 anddipyyromethane-dicarbinol 30-diol⁶⁴ with catalysis by InCl₃ followed byoxidation with DDQ gave the free base porphyrin. Metalation gave zincporphyrin Zn44 in 11.3% overall yield. Deprotection using 5 equiv ofTMS-Br and 6.7 equiv of TEA per phosphonate group afforded porphyrinZn46 in 82% yield (Scheme 16).

Similarly, a porphyrin was prepared that bears a free ethynyl group forSonogashira oligomerization with porphyrin monomers. The ethynyl unitwas incorporated via 43-diol. The condensation of 42 and 43-diol inCH₂Cl₂ with Yb(OTf)₃ as catalyst⁵³ followed by oxidation with DDQ gavethe free base porphyrin. Metalation afforded zinc porphyrin Zn45 in 24%yield (Scheme 16).

2. Chemical Characterization and Solubility Properties. All porphyrinswere characterized by absorption spectroscopy, ¹H NMR spectroscopy, LDMSand FABMS. The phosphonate-containing compounds generally were alsocharacterized by ³¹P NMR spectroscopy using H₃PO₄ as an externalstandard. In a few cases, solubility limited purification and analysis.Tri-p-tolylporphyrin Zn31 was sparingly soluble (CHCl₃, THF, or toluene)while trimesitylporphyrin Zn24 displayed good solubility in thesesolvents. The greater bulk of the mesityl versus p-tolyl groupsuppresses cofacial aggregation between porphyrins. The free baseanalogs of both these porphyrins display good solubility. The limitedsolubility of Zn31 but not its free base analog is attributed tocoordination of the dialkyl phosphonate of one porphyrin to the apicalsite of the zinc porphyrin of another porphyrin. Each porphyrin bearinga tripodal phosphonate tether displayed good solubility in commonorganic solvents. Porphyrin Zn46, which bears three phosphonic acidgroups, was quite soluble in water as well as organic solvents.

Experimental Section

General. ¹H NMR (400 MHz) and ¹³C NMR (100 MHz) spectra were recorded inCDCl₃ unless noted otherwise. Mass spectra of porphyrinic compounds wereobtained by FABMS, laser desorption mass spectrometry in the absence ofa matrix (LDMS), and/or MALDI-MS using the matrix1,4-bis(5-phenyloxazol-2-yl)benzene (POPOP). Absorption and emissionspectra were collected in toluene at room temperature unless notedotherwise. Melting points are uncorrected. Silica gel (40 μm averageparticle size) was used for column chromatography. Alumina activitygrade I was deactivated to grade V for chromatography ofmagnesium-porphyrinic compounds. Phosphoric acid (H₃PO₄) was used asexternal standard (referenced to δ 0.00 ppm) for ³¹P NMR (161.98 MHz)spectroscopy. Preparative SEC was performed as described previously.⁵⁹All Pd-mediated coupling reactions were carried out under argon usingstandard Schlcnk techniques.⁵⁸

Non-Commercial Compounds. 4-Bromobenzaldehyde dimethylacetal,⁴⁶4-bromomethylbenzaldehyde,⁶²Zn(II)-5-(4-iodophenyl)-10,20-dimesityl-15-[4-[2-(trimethylsilyl)ethynyl]phenyl]porphyrin,⁵⁷5-[4-(2-trimethylsilyl]ethynylphenyl)-1,9-bis(4-methylbenzoyl)dipyrromethane,⁵⁸5,⁵¹ 7-9,⁵² 13,⁵⁴ 14,⁵⁴ 19,⁵⁵ Zn22,⁵⁶ 30,⁶⁴ 32,⁶⁵ and 36²⁷ weresynthesized according to literature procedures.

Solvents. Toluene and TEA were freshly distilled from CaH₂ and spargedof oxygen prior to use. THF was distilled from sodium. CH₃CN wasdistilled from CaH₂ and stored over molecular sieves. All other solventswere used as received. CHCl₃ stabilized with 0.8% ethanol was used forthe porphyrin-formiing reactions and chromatography procedures. CHCl₃stabilized with amylenes (not ethanol) was used for the cleavage ofdialkyl phosphonates.

4-(Di-tert-butyloxyphosphoryl)benzaldehyde dimethylacetal. Samples of4-bromobenzaldehyde dimethylacetal (5.0 g, 22 mmol) anddi-tert-butylphosphite (5.1 g, 27 mmol) were coupled using Pd(PPh₃)₄(1.3 g, 1.1 mmol) in toluene/TEA [10 mL, (1:1)] at 80° C. under argonfor 20 h. A precipitate was formed during the course of the reaction.The reaction mixture was filtered and the filtrate was concentrated.Column chromatography [silica, hexanes/ethyl acetate (8:2)→ethylacetate/MeOH (9:1)] afforded a yellow oil (4.00 g, 53%): bp 152° C.; ¹HNMR δ 1.46 (s, 18 H), 3.34 (s, 6H), 5.41 (s, 1H), 7.48-7.52 (m, 2H),7.76-7.83 (m, 2H); ¹³C NMR δ 30.8, 30.9, 52.7, 82.3, 82.4, 103.4, 127.3,127.4, 132.1, 132.2, 142.6, 142.7; ³¹P NMR (THF-d₈) δ 10.6; Anal. Calcdfor C₁₇H₂₉O₅P: C, 59.29; H, 8.49. Found: C, 59.18; H, 8.49.

5-[4-(Di-tert-butyloxyphosphoryl)phenyl]-10,15,20-trimesitylporphyrin(1). Samples of mesitaldehyde (1.34 g, 9.00 mmol),4-(di-tert-butyloxyphosphoryl)benzaldehyde dimethylacetal (1.00 g, 3.00mmol), and pyrrole (805 mg, 12.0 mmol) were condensed in CHCl₃ (1.2 L)containing ethanol as a stabilizer was treated with BF₃.O(Et)₂ (500 μL)at room temperature for 1.5 h. DDQ (2.04 g, 9.00 mmol) was added. After1 h, TEA was added and the reaction mixture was concentrated. Columnchromatography [silica, CHCl₃/hexanes (1:1)→CHCl₃/ethyl acetate (8:2);silica, CHCl₃/ethyl acetate (8:2)] afforded a purple solid (255 mg,6.8%): ¹H NMR δ-2.58 (br s, 2H), 1.65 (s, 18H), 1.84-1.85 (m, 18H), 2.62s, 9H), 7.27 (s, 6H), 8.14-8.27 (m, 4H), 8.64-8.73 (m, 8H); ³¹P NMR(THF-d₈) δ 10.7; LDMS obsd 934.0, 877.2 [(M-tert-Bu)⁺]; 821.01[(M-2×tert-Bu)⁺]; FABMS obsd 932.4788; calcd 932.4794 (C₆₁H₆₅N₄O₃P);λ_(abs) 420, 514, 547, 592, 650 nm; λ_(em) (λ_(ex)=550) 650, 719 nm.

Zn(II)-5-[4-(Di-tert-butyloxyphosphoryl)phenyl]-10,15-20-trimesitylporphyrin(Zn1). A solution of 1 (0.210 g, 0.225 mmol) in CHCl₃ (50 mL) wastreated overnight with Zn(OAc)₂.2H₂O (0.250 g, 1.14 mmol) in methanol (5mL) at room temperature. The reaction mixture was washed with water,dried (Na₂SO₄) and chromatographed [silica, CHCl₃/ethyl acetate (9:1)]to afford a purple solid (163 mg, 73%): ¹H NMR δ 1.64 (s, 18H), 1.84 (s,18H), 2.62 (s, 9H), 7.27 (s, 6H), 8.07-8.28 (m, 4H), 8.64-8.75 (m, 8H);³¹P NMR (THF-d₈) δ 11.1; LDMS obsd 993.5, 881.9 [(M-2×tert-Bu)⁺]; FABMSobsd 994.3925; calcd 994.3929 (C₆₁H₆₃N₄O₃PZn); λ_(abs) 423, 550 nm;λ_(em)(λ_(ex)=550 nm) 600, 649 nm.

Zinc(II)-5-[4-(Diethoxyphosphoryl)phenyl]-10,15,20-trimesitylporphyrin(Zn3). A solution of porphyrin 3 (0.080 g, 0.090 mmol) in CHCl₃/methanol(8:1) was treated overnight with Zn(OAc)₂.2H₂O (0.099 g, 0.45 mmol).Standard workup including chromatography [silica, CHCl₃/methanol (98:2)]afforded a purple solid (0.071 g, 85%): 1H NMR δ 1.17 (t, J=7.2 Hz, 6H), δ 1.80-1.88 (m 18H), 2.58-2.65 (m, 9H), 3.60-3.75 (m, 4H), 7.28 (s,6H), 7.43-7.55 (m, 2H), 8.12-8.21 (m, 2H), 8.65-8.78 (m, 8H); LDMS obsd937.9; FABMS obsd 938.3339, calcd 938.3303 (C₅₇H₅₅N₄O₃PZn); λ_(abs) 423,549 nm.

Mg(II)-5-[4-(Di-tert-butyloxyphosphoryl)phenyl]-10,15-20-trimesitylporphyrin(Mg1). A solution of 1 (23 mg, 0.025 mmol) in CH₂Cl₂ (1 mL) was treatedwith the ethereal MgI₂-DIEA reagent (7 mL, ˜0.04 M solution of MgI₂) andthe mixture was stirred at room temperature for 1 h. The mixture wasdiluted with CH₂Cl₂ and washed with aqueous 5% NaHCO₃ and water, dried(Na₂SO₄) and concentrated. Trituration with hexanes afforded a purplesolid (17 mg, 71%): ¹H NMR (THF-d₈) δ 1.63 (s, 18H), 1.82-1.89 (m, 18H),2.58-2.63 (s, 9H), 7.27 (s, 6H), 8.05-8.15 (m, 2H), 8.21-8.29 (m, 2H),8.52-8.56 (m, 6H), 8.63-8.66 (m, 2H); ³¹P NMR (THF-d₈) δ 11.31; LDMSobsd 956.3, 901.2 [(M-tert-Bu)⁺], 843.8 [(M-2×tert-Bu)⁺]; FABMS obsd954.4443; calcd 954.4488 (C₆₁H₆₃MgN₄O₃P); λ_(dabs) (THF) 431, 573, 614nm.

5-(4-Dihydroxyphosphorylphenyl)-10,15,20-trimesitylporphyrin (2). Asample of Zn3 (175 mg, 0.200 mmol) in CH₂Cl₂ (20 mL) was treated with 16equiv of TMS-Br (0.420 mL, 3.20 mmol). The green mixture was stirredovernight at room temperature. The solvent was evaporated to afford agreen residue. The green residue was suspended in water and thesuspension was stirred at room temperature for 2 h. The mixture wasextracted with CHCl₃. The CHCl₃ layer was washed with saturated aqueousNaHCO₃, water and dried (Na₂SO₄). The solution was concentrated.Chromatography [silica, CHCl₃/MeOH (1:1)] afforded a purple solid (130mg, 79%): ¹H NMR δ-2.74 (br s, 2H), 1.76 (s, 18H), 2.57 (s, 9H),7.12-7.26 (m, 4H), 7.32 (s, 2H), 8.04-8.16 (m, 4H), 8.46-8.62 (m, 6H),8.74-8.82 (m, 2H); LD-MS obsd 820.9; FAB-MS obsd 820.3560, calcd820.3542 (C₅₃H₄₉N₄O₃P); λ_(abs) (THF) 419, 515, 550, 592, 648 nm.

Zn(II)-5-[4-(Dihydroxyphosphoryl)phenyl]-10,15,20-trimesitylporphyrin(Zn2; from Zn1). A mixture of Zn1 (150 mg, 0.150 mmol), TMS-Cl (287 μL,2.25 mmol) and TEA (300 μL, 3 mmol) in CHCl₃ (15 mL) was stirred atreflux (˜65° C.) under argon for 4 h. The reaction mixture was washedwith water, dried (Na₂SO₄) and chromatographed [silica, CHCl₃/ethylacetate (1:1)→CHCl₃/MeOH (1:1)] to afford a purple solid (118 mg, 89%):¹H NMR δ 1.70-1.76 (m, 18H), 2.50-2.51 (m, 9H), 7.20-7.26 (m, 6H),8.10-8.11 (m, 2H), 8.28-8.29 (m, 2H), 8.50-8.51 (m, 6H), 8.70-8.71 (m,2H); ³¹P NMR (THF-d₈) δ 12.2; LDMS obsd 885.70; FABMS obsd 881.49; calcd882.27 (C₅₃H₄₇N₄O₃PZn); λ_(abs) 420, 550 nm; λ_(em) 596, 645 nm.

Zn2 from Zn3. A mixture of Zn3 (30 mg, 0.032 mmol), TMS-Br (66 μL, 0.50mmol) and TEA (66 μL, 0.63 mmol) in CHCl₃ (4 mL) was stirred at refluxfor 4 h. The reaction mixture was diluted with CH₂Cl₂ (100 mL), washedwith water, dried (Na₂SO₄) and chromatographed [silica, CHCl₃/ethylacetate (1:1)→CHCl₃/MeOH (1:1)] to afford a purple solid (23 mg, 81%).Characterization data were consistent with those reported above.

Zn2 by metalation of 2. A solution of porphyrin 2 (0.123 g, 0.150 mmol)in CHCl₃/methanol (15 mL, 2:1) was treated overnight with Zn(OAc)₂.2H₂O(0.329 g, 1.50 mmol). Standard workup including chromatography [silica,CHCl₃/MeOH (1:1)] afforded a purple solid (0.103 g, 77%).Characterization data were consistent with those reported above.

Mg(II)-5-[4-(Dihydroxyphosphoryl)phenyl]-10,15,20-trimesitylporphyrin(Mg2). A sample of Mg1 (14 mg, 0.015 mmol) in CHCl₃ (5 mL) was treatedwith TEA (0.041 mL, 0.30 mmol) and TMS-Br (0.030 mL, 0.23 mmol). Thecloudy mixture was stirred at reflux for 4 h. Water was added and themixture was extracted with CHCl₃. The organic layer was dried (Na₂SO₄)and concentrated. Trituration with hexanes afforded a purple solid (10mg, 77%): ¹H NMR (THF-d₈) δ 1.75-1.90 (m, 18H), 2.50-2.70 (m, 9H),7.15-7.35 (m, 6H), 8.10-8.35 (m, 4H), 8.45-8.62 (m, 6H), 8.68-8.82 (m,2H); ³¹P NMR (THF-d₈) δ 14.37; MALDI-MS (POPOP) obsd 843.5, 821.5[(M-Mg)⁺]; FABMS obsd 842.3239; calcd 842.3236 (C₅₃H₄₇MgN₄O₃P); λ_(abs)(THF) 431, 574, 614 nm.

5-[4-(Di-tert-butyloxyphosphoryl]phenyl dipyrromethane (6). Method A: Asolution of 4 (3.44 g, 10.0 mmol) and pyrrole (17.4 mL, 0.250 mol) inCH₂Cl₂ (20 mL) was treated with TFA (77 μL, 1.0 mmol) under argon for 2h at room temperature. Then 0.1 M NaOH was added. The mixture was pouredinto brine and ethyl acetate. The organic phase was isolated, washedwith water, dried (Na₂SO₄) and concentrated. Column chromatography[silica, CH₂Cl₂/ethyl acetate (3:1)] afforded an orange oil.Recrystallization [ethanol/water (1:1)] afforded a pale brown powder(1.3 g, 31%): mp 138-139° C.; ¹H NMR δ 1.44 (s, 18H), 5.51 (s, 1H), 5.93(s, 2H), 6.13-6.15 (m, 2H), 6.69-6.71 (m, 2H), 7.13-7.22 (m, 2H),7.52-7.62 (m, 2H), 8.68 (br s, 2H); ¹³C NMR δ 30.46, 30.50, 43.9, 82.61,82.68, 107.4, 107.9, 117.7, 128.1, 128.2, 130.2, 131.4, 131.5, 132.05,132.11, 146.49, 146.52; ³¹P NMR δ 10.94; Anal. Calcd for C₂₃H₃₁N₂O₃P: C,66.65; H, 7.54; N, 6.76. Found: C, 66.57; H, 7.41; N, 6.65.

Method B: Samples of 5 (1.0 g, 3.4 mmol) and Pd(PPh₃)₄ (200 mg, 0.17mmol) in TEA (1 mL) and toluene (1 mL) was treated withdi-tert-butylphosphite (740 mg, 3.8 mmol). The reaction mixture wasstirred under argon at 85° C. for 20 h, then concentrated andchromatographed [silica, CHCl₃/ethyl acetate (3:1)] to afford a lightbrown solid (600 mg, 43%). Characterization data were consistent withthose described above.

5,15-Bis(pentafluorophenyl)-10-[4-(di-tert-butyloxyphosphoryl)phenyl]-20-(4-iodophenyl)porphyrin(10). A solution of 7 (888 mg, 1.21 mmol) in THF/methanol [55 mL (10:1)]was treated with NaBH₄ (915 mg, 24.2 mmol). The resultingdipyrromethane-dicarbinol (7-diol) was condensed with 6 (0.500 g, 1.21mmol) in CH₂Cl₂ (484 mL) containing Yb(OTf)₃ (954 mg, 1.53 mmol, 3.2mM). After 20 min, a sample of DDQ (824 mg, 3.63 mmol) was added. After30 min, TEA was added followed by filtration through a silica pad[CH₂Cl₂/ethyl acetate (5:1)]. Column chromatography [silica, CHCl₃/MeOH(98:2)] followed by trituration with methanol afforded a purple solid(62 mg, 4.6%): ¹H NMR δ-2.88 (br s, 2H), 1.68 (s, 18H), 7.95 (d, J=6.8Hz, 2H), 8.13 (d, J=6.8 Hz, 2H), 8.19-8.29 (m, 4H), 8.82-8.83 (m, 4H),8.91 (d, J=4.8 Hz, 2H), 8.94 (d, J=4.8 Hz, 2H); LDMS obsd 1114.1, 1058.0[(M-tert-Bu)⁺], 1000.9 [(M-2×tert-Bu)⁺]; FABMS obsd 1112.1429; calcd1112.1410 (C₅₂H₃₆F₁₀IN₄O₃P). λ_(abs) 419, 512, 544, 589, 643 nm; λ_(em)(λ_(ex)=513 nm) 647, 715 nm.

5,15-Bis(pentafluorophenyl)-10-[4-(di-tert-butyloxyphosphoryl)phenyl]-20-[4-(2-(trimethylsilyl)ethynyl)phenyl]porphyrin(11). A solution of 8 (1.02 g, 1.45 mmol) in THF/methanol [55 mL (10:1)]was treated with NaBH₄ (1.10 g, 29.0 mmol). The resultingdipyrromethane-dicarbinol (8-diol) was condensed with 6 (600 mg, 1.45mmol) in CH₃CN (580 mL) containing TFA (1.34 mL, 17.4 mmol, 30 mM).After 6 min, a sample of DDQ (824 mg, 3.63 mmol) was added. After 30min, TEA was added and the mixture was filtered through a silica pad[CH₂Cl₂/ethyl acetate (5:1)]. The porphyrin-containing fractions (whichcontained a large amount of dipyrrin) were combined and concentrated.Trituration with methanol followed by filtration afforded a purple solid(123 mg, 7.8%): ¹H NMR δ-2.86 (br s, 2H), 0.39 (s, 9H), 1.68 (s, 18H),7.90 (d, J=7.6 Hz, 2H), 8.17 (d, J=7.6 Hz, 2H), 8.19-8.29 (m, 4H),8.83-8.84 (m, 4H), 8.91-8.94 (m, 4H); ³¹P NMR δ 10.14; LDMS obsd 1083.7,1027.7 [(M - tert-Bu)⁺], 971.4 [(M-2×tert-Bu)⁺]; FABMS obsd 1082.2810;calcd 1082.2839 (C₅₇H₄₅F₁₀N₄O₃PSi). λ_(abs) 419, 512, 545, 589, 644 nm;λ_(em) (λ_(ex) 512 nm) 648, 715 nm.

5-[4-(Di-tert-butyloxyphosphoryl)phenyl]-10-(4-iodophenyl)-15-mesityl-20-[4-(2-(trimethylsilyl)ethynyl)phenyl]porphyrin(12). A solution of 9 (0.347 g, 0.500 mmol) in THF/methanol [33 mL(10:1)] was treated with NaBH₄ (0.380 g, 10.0 mmol). The resultingdipyrromethane-dicarbinol (9-diol) was condensed with 6 (0.207 g, 0.500mmol) in CH₃CN (200 mL) containing TFA (0.460 mL, 6.00 mmol, 30 mM).After 5 min, a sample of DDQ (0.340 mg, 1.50 mmol) was added. After 1 h,TEA was added and the mixture was filtered through a silica pad[CHCl₃/ethyl acetate (95:5)]. The porphyrin-containing fractions werecombined, concentrated and chromatographed [silica, CHCl₃/ethyl acetate(90:10) to afford a purple solid (127 mg, 25%): ¹H NMR δ-2.73 (br s,2H), 0.39 (s, 9H), 1.68 (s, 18H), 1.84 (s, 6H), 2.64 (s, 3H), 7.29 (s,2H), 7.88 (d, J=8.4 Hz, 2H), 7.96 (d, J=8.4 Hz, 2H), 8.09 (d, J=8.4 Hz,2H), 8.15-8.30 (m, 6H), 8.70-8.75 (m, 2H), 8.76-8.90 (m, 6H); ³¹P NMR δ10.14; LDMS obsd 1072.2, 960.7 [(M-tert-Bu)⁺], 834.3 [(M-2×tert-Bu)⁺];FABMS obsd 1070.3202; calcd 1070.3217 (C₆₀H₆₀IN₄O₃PSi). λ_(abs) 422,515, 550, 592, 648 nm.

5-[4-(Di-tert-butyloxyphosphoryl)phenyl]-1-p-toluoyldipyrromethane (15).A solution of EtMgBr (5 mL, 5 mmol, 1.0 M in THF) was added to asolution of 6 (829 mg, 2.00 mmol) in THF (2 mL) under Ar. The mixturewas stirred at room temperature for 10 min and then cooled to −78° C. Asolution of 13 (459 mg, 2.00 mmol) in THE (2 mL) was added over 1 min.The solution was maintained at —78° C. for 10 min, and then the coolingbath was removed. After 30 min, the reaction was quenched with saturatedaqueous NH₄Cl. The mixture was allowed to warm to room temperature,poured into CH₂Cl₂, washed with water and then dried (Na₂SO₄). Columnchromatography (silica, CH₂Cl₂/ethyl acetate (3:1)] afforded a paleyellow solid (512 mg, 48%): mp 97-99° C.; ¹H NMR δ 1.44 (s, 18H), 2.42(s, 3H), 5.59 (s, 1H), 5.93-5.98 (m, 1H), 6.01-6.07 (m, 1H), 6.12-6.16(m, 1H), 6.65-6.69 (m, 1H), 6.78-6.82 (m, 1H), 7.20-7.28 (m, 4H),7.64-7.74 (m, 4H), 8.68 (br s, 1H), 9.97 (br s, 1H); ¹³C NMR δ 21.6,30.39, 30.43, 44.0, 82.3, 82.4, 107.7, 108.0, 110.9, 118.1, 121.2,127.9, 128.1, 129.0, 129.1, 130.6, 130.8, 131.2, 131.6, 131.7, 133.2,135.6, 141.6, 142.4, 144.58, 144.61, 184.8; ³¹P NMR δ 10.30; Anal. Calcdfor C₃₁H₃₇N₂O₄P: C, 69.91; H, 7.00; N, 5.26. Found: C, 69.91; H, 7.11;N, 5.15.

5-[4-(Di-tert-butyloxyphosphoryl)phenyl]-1-[4-[2-trimethylsilyl)ethynyl]benzoyl]dipyrromethane(16). Following the procedure described for compound 15, reaction of 6(829 mg, 2.00 mmol) and 14 (623 mg, 2.00 mmol) followed by columnchromatography [silica, CH₂Cl₂/ethyl acetate (3:1)] afforded a paleyellow solid (853 mg, 69%): mp 116-117° C.; ¹H NMR δ 0.26 (s, 9H), 1.45(s, 18H), 5.58 (s, 1H), 5.93-5.99 (m, 1H), 6.03-6.09 (m, 1H), 6.12-6.18(m, 1H), 6.70 (s, 1H), 6.73-6.80 (m, 1H), 7.19-7.27 (m, 2H), 7.53 (d,J=8.0 Hz, 2H), 7.65-7.78 (m, 4H), 8.45 (br s, 1H), 9.82 (br s, 1H); ¹³CNMR δ-0.12, 30.43, 30.46, 44.0, 82.3, 82.42, 82.45, 82.49, 82.53, 97.3,104.2, 107.8, 108.1, 111.2, 118.2, 121.5, 126.6, 127.9, 128.1, 128.8,130.4, 130.6, 131.3, 131.6, 131.7, 131.8, 133.3, 137.9, 142.1, 144.49,144.53, 183.9; ³¹P NMR δ 10.26; Anal. Calcd for C₃₅H₄₃N₂O₄PSi: C, 68.38;H, 7.05; N, 4.56. Found: C, 68.51; H, 7.12; N, 4.51.

5,15-Bis[4-(di-tert-butyloxyphosphoryl)phenyl]-10,20-di-p-tolylporphyrin(17). A solution of 15 (266 mg, 0.500 mmol) in THF/methanol [9 mL,(3:1)] was treated with NaBH₄ (475 mg, 12.5 mmol). The resultingcarbinol (15-OH) was dissolved in CH₃CN (100 mL) and treated with TFA(230 μL, 3.0 mmol, 30 mM). After 5 min, a sample of DDQ (170 mg, 0.75mmol) was added. After 1 h, TEA (420 μL, 3.0 mmol) was added. Themixture was concentrated and chromatographed [silica, CH₂Cl₂/ethylacetate (3:1)], affording a purple solid (72 mg, 28%): ¹H NMR δ-2.78 (brs, 2H), 1.68 (s, 36H), 2.71 (s, 6H), 7.56 (d, J=8.0 Hz, 4H), 8.10 (d,J=8.0 Hz, 4H), 8.16-8.23 (m, 4H), 8.26-8.33 (m, 4H), 8.80 (d, J=4.8 Hz,4H), 8.91 (d, J=4.8 Hz, 4H); ³¹P NMR δ 10.41; LDMS obsd 1027.6, 972.5[(M-tert-Bu)⁺], 915.9 [(M-2×tert-Bu)⁺], 860.3 [(M-3×tert-Bu)⁺], 802.8[(M-4×tert-Bu)⁺]; FABMS obsd 1026.4604; calcd 1026.4614 (C₆₂H₆₈N₄O₆P₂);λ_(abs) (THF) 418, 514, 548, 592, 647 nm.

1-Bromo-5-[4-(di-tert-butyloxyphosphoryl)phenyl]-9-p-toluoyldipyrromethane(18). A solution of 15 (266 mg, 0.500 mmol) in THF (10 mL) was cooled to−78° C. under Ar. A sample of NBS (89 mg, 0.50 mmol) was added and thereaction mixture was stirred for 1 h at −78° C. Hexanes (10 mL) andwater (10 mL) were added and the mixture was allowed to warm to roomtemperature. The organic phase was extracted with CH₂Cl₂, dried (Na₂SO₄)and concentrated under reduced pressure without heating. Columnchromatography [silica, CH₂Cl₂/ethyl acetate (3:1)] afforded a palebrown powder (239 mg, 78%): mp 132-134° C. (dec.); ¹H NMR δ 1.44 (s,18H), 2.42 (s, 3H), 5.55 (s, 1H), 5.85-5.90 (m, 1H), 6.00-6.06 (m, 1H),6.07-6.09 (m, 1H), 6.70-6.81 (m, 1H), 7.10-7.26 (m, 4H), 7.60-7.70 (m,4H), 9.20 (br s, 1H), 10.38 (br, 1H); ¹³C NMR δ 30.66, 30.70, 44.3,82.7, 82.8, 98.4, 109.9, 110.3, 111.4, 121.6, 128.1, 128.2, 129.2,129.5, 131.2, 131.6, 131.9, 132.0, 132.3, 133.6, 135.7, 141.2, 142.7,144.2, 144.3, 185.3; ³¹P NMR δ 9.99; Anal. Calcd for C₃₁H₃₆BrN₂O₄P: C,60.89; H, 5.93; N, 4.58. Found: C, 59.93; H, 6.07; N, 4.10.

Zn(II)-10-[4-(Di-tert-butyloxyphosphoryl)phenyl]-17,18-dihydro-18,18-dimethyl-5-p-tolylporphyrin(Zn20). A solution of 18 (183 mg, 0.300 mmol) in THF/methanol [12.5 mL(4:1)] was treated with NaBH₄ (114 mg, 3.00 mmol). After 15 min, thereaction mixture was quenched with cold water and extracted with CH₂Cl₂.The organic layer was dried (K₂CO₃) and concentrated under reducedpressure without heating to afford mono-carbinol 18-OH as a foam. Thelatter was dissolved in CH₃CN (3 mL) and 19 (57 mg, 0.30 mmol) was addedfollowed by TFA (23 μL, 0.30 mmol). The reaction mixture was stirred atroom temperature for 30 min, and then diluted with 27 mL of CH₃CN.Samples of AgOTf (231 mg, 0.900 mmol), Zn(OAc)₂ (826 mg, 4.50 mmol), and2,2,6,6-tetramethylpiperidine (2.4 mL, 9.0 mmol) were added. Theresulting mixture was refluxed for 18 h exposed to air. The mixture wasconcentrated. Column chromatography [silica, CH₂Cl₂/ethyl acetate (3:1)]afforded a purple-green solid (39 mg, 17%): ¹H NMR (THF-d₈) δ 1.57 (s,18H), 2.04 (s, 6H), 2.65 (s, 3H), 4.53 (s, 2H), 7.49 (d, J=7.6 Hz, 2H),7.93 (d, J=7.6 Hz, 2H), 7.96-8.02 (m, 2H), 8.07-8.14 (m, 2H), 8.23 (d,J=4.4 Hz, 1H), 8.31 (d, J=4.4 Hz, 1H), 8.50 (d, J=4.4 Hz, 1H), 8.55-8.65(m, 5H); ³¹P NMR δ 14.32; LDMS obsd 763.2, 700.1 [(M-tert-Bu)⁺], 648.8[(M-2×tert-Bu)⁺], 586.6 [[M-(2×tert-Bu)-Zn]⁺]; FABMS obsd 760.2548;calcd 760.2521 (C₄₃H₄₅N₄O₃PZn); λ_(abs) (THF) 412, 607 nm.

Zn(II)-17,18-Dihydro-10-[4-(dihydroxyphosphoryl)phenyl]-18,18-dimethyl-5-p-tolylporphyrin(Zn21). A solution of Zn20 (20.0 mg, 26.0 μmol) in CHCl₃ (5 mL) wastreated with TEA (0.073 mL, 0.52 mmol) and TMS-Cl (0.049 mL, 0.39 mmol).The cloudy mixture was stirred at reflux for 4 h, at which time TLCindicated the absence of starting material [R_(f) for Zn20=1, R_(f) forZn21=0.1 (CHCl₃/MeOH, 1:1)]. Water was added and the organic phase wasextracted with CHCl₃, dried (Na₂SO₄) and concentrated. Trituration withhexanes afforded a purple solid (15 mg, 88%): The acquisition of ¹H and³¹P NMR in CDCl₃, THF-d_(8,) CD₃OD, or DMSO-d₆ did not show any clearindication of peaks; MALDI-MS (POPOP) obsd 648.5, calcd 648.1(C₃₅H₂₉N₄O₃PZn); λ_(abs) (THF) 414, 608 nm. A FABMS spectrum gave veryweak, uninformative signals.

Zn(II)-5-[4-(Di-tert-butyloxyphosphoryl)phenyl]-10,20-dimesityl-15-[4-[2-(trimethylsilyl)ethynyl]phenyl]porphyrin(Zn23). Samples ofZn(II)-5-(4-iodophenyl)-10,20-dimesityl-15-[4-[2-(trimethylsilyl)ethynyl]phenyl]porphyrin(191 mg, 194 μmol) and di-tert-butylphosphite (388 μmol, 1.94 mmol) werecoupled using [Pd(PPh₃)₄] (22 mg, 19 μmol) in toluene/TEA [6 mL, (5:1)]at 80° C. under argon for 16 h. Column chromatography [silica,CHCl₃→CHCl₃/MeOH (10:1); silica, CHCl₃/MeOH (4:1)] followed bytrituration with hexanes afforded a purple solid (94 mg, 46%): ¹H NMR(THF-d₈) δ 0.36 (s, 9H), 1.63 (s, 18H), 1.84 (s, 12H), 2.61 (s, 6H),7.30 (s, 4H), 7.81 (d, J=8.0 Hz, 2H), 8.11-8.14 (m, 2H), 8.18 (d, J=8.0Hz, 2H), 8.24-8.27 (m, 2H), 8.66-8.68 (m, 4H), 8.75-8.78 (m, 4H); LDMSobsd 1050.5, 996.6 [(M-tert-Bu)⁺], 935.6 [(M-2×tert-Bu)⁺]; FABMS obsd1048.3855; calcd 1048.3867 (C₆₃H₆₅N₄O₃PSiZn); λ_(abs) 424, 483, 514,550, 590 nm; λ_(em) (λ_(ex)=550 nm) 597, 646 nm.

Dyad-1. Samples of Zn23 (49 mg, 0.050 mmol) and Zn22 (47 mg, 0.050 mmol)were treated with Pd₂(dba)₃ (6.9 mg, 7.5 μmol) and P(o-tol)₃ (18 mg,0.06 mmol) in toluene/TEA [18 mL, (5:1)] at 35° C. under argon. After 4h, an identical batch of catalyst was added. The reaction was continuedfor another 7 h. Purification by a silica column [CHCl₃/MeOH (98:2)], apreparative SEC column (THF), and a short silica column [CHCl₃/MeOH(98:2)] afforded a brown-purple solid (48 mg, 54%): ¹H NMR (THF-d₈) δ1.65 (s, 18H), 1.85-1.91 (m, 30H), 2.59-2.65 (m, 15H), 7.28-7.34 (m,10H), 8.03-8.08 (m, 4H), 8.12-8.19 (m, 2H), 8.26-8.34 (m, 6H), 8.62-8.66(m, 4H), 8.68-8.72 (m, 4H), 8.74 (d, J=4.4 Hz, 2H), 8.78 (d, J=4.4 Hz,2H), 8.87 (d, J=4.4 Hz, 2H), 8.90 (d, J=4.4 Hz, 2H); ³¹P NMR δ 11.06;MALDI-MS (POPOP) obsd 1781.2, 1723.4 [(M-tert-Bu)⁺], 1667.0[(M-2×tert-Bu)⁺]; FABMS obsd 1776.6273; calcd 1776.6317(C₁₁₃H₁₀₁N₈O₃PZn₂); λ_(abs) 428, 551, 593 nm.

Dyad-2. A solution of Dyad-1 (31 mg, 0.017 mmol) and TEA (47 μL, 0.34mmol) in CHCl₃ (3.4 mL) was treated with TMS-Cl (33 μL, 0.26 mmol) at65° C. under argon for 4 h. Water was added and the organic layer wasdried (Na₂SO₄) and concentrated. Trituration with hexanes afforded apurple solid (23 mg, 82%): ¹H NMR (CD₃OD) δ 1.82-1.92 (m, 30H),2.57-2.65 (m, 15H), 7.25-7.34 (m, 10H), 7.98-8.06 (m, 4H), 8.18-8.23 (m,4H), 8.26-8.32 (m, 4H), 8.58-8.72 (m, 10H), 8.78-8.88 (m, 6H); ³¹P NMR δ(not observed); MALDI-MS (POPOP) obsd 1667.4; FABMS obsd 1664.5020;calcd 1664.5065 (C₁₀₅H₈₅N₈O₃PZn₂); λ_(abs) 428, 551, 591 nm.

5-[4-(Diethoxyphosphorylmethyl)phenyl]-10,15,20-trimesitylporphyrin (24)(Method A). A solution of 26 (200 mg, 240 μmol) in triethylphosphite(2.1 mL) and toluene (8 mL) was heated to 120° C. under argon for 24 h.The reaction mixture was cooled and concentrated under vacuum (to removeexcess triethylphosphite; bp=154° C.). Column chromatography [silica,CHCl₃→CHCl₃/ethyl acetate (95:5)] afforded a purple solid (165 mg, 80%).Characterization data were consistent with those described above.

(Method B). A solution of diethylphosphite (1.16 mL, 9.00 mmol) in THF(20 mL) was treated with NaH (206 mg, 8.60 mmol) and the mixture wasstirred at room temperature under argon for 1 h. A 1.9 mL aliquot ofthis solution (864 mmol, 3 eq) was then added to a solution of 26 (240mg, 288 mol) in THF (20 mL). The reaction mixture was stirred at underargon for 24 h. Water and CH₂Cl₂ were added. The layers were separatedand the aqueous layer was washed with CH₂Cl₂. The organic layers werecombined, dried (K₂CO₃), and concentrated. Column chromatography[silica, CHCl₃→CHCl₃/ethyl acetate (95:5)] afforded a purple solid (187mg, 73%). Characterization data were consistent with those describedabove.

Zn(II)-5-[4-(Diethoxyphosphorylmethyl)phenyl]-10,15,20-trimesitylporphyrin(Zn24). A solution of 24 (163 mg, 189 μmol) in CHCl₃ (15 mL) was treatedwith a solution of Zn(OAc)₂.2H₂O (207 mg, 943 μmol) in methanol (3 mL).Column chromatography [silica, CHCl₃/ethyl acetate (95:5)] afforded apurple solid (164 mg, 94%): ¹H NMR (THF-d₈) δ 1.35 (t, J=6.9 Hz, 6H),1.86 (s, 18H), 2.61 (s, 9H), 3.46 (d, J=22.0 Hz, 2H), 4.14 (p, J=7.2 Hz,4H), 7.29 (s, 6H), 7.70 (dd, J¹=7.5 Hz, J²=1.8 Hz, 2H), 8.11 (d, J=7.5Hz, 2H), 8.62-8.63 (m, 6H), 8.76 (d, J=4.5 Hz, 2H); ³¹P NMR δ 26.8; LDMSobsd 956.0; FABMS obsd 952.3466; calcd 952.3460 (C₅₈H₅₇N₄O₃PZn);λ_(abs)=425, 555, 595 nm.

Co(II)-5-[4-(Diethoxyphosphorylmethyl)phenyl]-10,15,20-trimesitylporphyrin(Co24). A solution of 24 (184 mg, 206 μmol) in CHCl₃ (100 mL) wastreated with a suspension of Co(OAc)₂ (365 mg, 2.06 mmol) in methanol(20 mL). The mixture was heated to reflux under argon. After 12 h, themixture was cooled and washed with water. The organic layer was dried(K₂CO₃), filtered, and concentrated. Column chromatography [silica,CHCl₃/ethyl acetate (9:1)] afforded a red solid (133 mg, 68%): ¹H NMR δ2.23 (t, J=6.3 Hz, 6H), 3.28 (br s, 6H), 3.58 (br s, 12H), 3.93 (s, 3H),4.01 (s, 6H), 4.81 (d, J=21.6 Hz, 2H), 5.12 (m, 4H), 9.17 (s, 2H), 9.30(s, 4H), 9.66 (s, 2H), 12.49 (br s, 2H), 15.25 (br s, 4H), 15.50 (br s,4H); LDMS obsd 948.9. FABMS obsd 947.3525, calcd 947.3500(C₅₈H₅₇CoN₄O₃P); λ_(abs)=412, 528 nm.

Co(II)-5-[4-(Dihydroxyphosphorylmethyl)phenyl]-10,15,20-trimesitylporphyrin(Co25). A solution of Co24 (126 mg, 133 μmol) in CHCl₃ (13 mL) wastreated with samples of TEA (371 μL, 2.66 mmol) and TMS-Br (263 μL, 2.00mmol) at reflux under argon for 4 h. The mixture was cooled and thenwashed with water. The organic layer was dried (Na₂CO₃), filtered andconcentrated. The resulting red solid was washed with hexanes to afforda red solid (110 mg, 92%): ¹H NMR analysis was not successful due bothto aggregation and the paramagnetic Co(II). LDMS obsd 891.1; FABMS obsd891.2883, calcd 891.2874 (C₅₄H₄₉CoN₄O₃P); λ_(abs)=413, 529 nm.

Zn(II)-5-[4-(Dihydroxyphosphorylmethyl)phenyl]-10,15,20-trimesitylporphyrin(Zn25; from Zn24). A mixture of Zn24 (178 mg, 186 μmol) in CHCl₃ (18 mL)and TEA (518 μL, 3.72 mmol) was heated to reflux, affording ahomogeneous solution. A sample of TMS-Br (369 μL, 2.80 mmol) was thenadded. The solution was stirred at reflux for 4 h, then cooled. Thereaction mixture was washed with water. The organic layer was collected,dried (Na₂SO₄), and concentrated. Column chromatography [silica,CHCl₃/MeOH (1:1)] afforded a purple solid. The solid was washed withhexanes, then water, then hexanes again to afford a purple solid (130mg, 78%): ¹H NMR (DMSO-d₆) δ 1.71 (s, 9H), 1.76 (s, 9H), 2.54 (s, 3H),the other methyl signal is presumed to be buried under the DMSO solventpeak, 7.20 (s, 3H), 7.36 (s, 3H), 7.69 (d, 2H), 7.97 (d, 2H), 8.47 (s,6H), 8.74 (s, 2H); ³¹P NMR analysis was attempted but no peak could beobserved; LDMS obsd 927.7 [(M+OMe)⁺]; FABMS obsd 896.2870; calcd896.2834 (C₄₈H₄₉N₄O₃PZn); λ_(abs)=426, 556, 596 nm; λ_(em) (λ_(ex)=556nm) 601, 655 nm.

Zn(II)-5-[4-(Dihydroxyphosphorylmethyl)phenyl]-10,15,20-trimesitylporphyrin(Zn25; from Zn27). A mixture of Zn27 (159 mg, 172 μmol) in CHCl₃ (17 mL)and TEA (479 μL, 3.44 mmol) was heated to reflux, affording ahomogeneous solution. A sample of TMS-Br (341 μL, 2.58 mmol) was thenadded. The solution was stirred at reflux for 2 h then cooled. Analogousworkup as described above yielded a purple solid (120 mg, 77%).Characterization data were consistent with those described above.

5-[4-(Bromomethyl)phenyl]-10,15,20-trimesitylporphyrin (26). Samples of4-bromomethylbenzaldehyde (700 mg, 3.52 mmol), mesitaldehyde (1.56 mL,10.6 mmol), and pyrrole (977 μL, 14.1 mmol) were condensed in CHCl₃ (193mL) in the presence of BF₃.O(Et)₂ (435 μL, 3.43 mmol) at roomtemperature for 1 h. DDQ (2.41 g, 10.6 mmol) was added. After 1 h, TEA(478 μmol, 3.43 mmol) was added and the crude mixture was passed over apad of silica [CH₂Cl₂/hexanes (1:1)] followed by column chromatography[silica, hexanes/CH₂Cl₂ (7:3), 10×30 cm] to afford a purple solid (465mg, 16%): ¹H NMR δ-2.57 (br s, 2H), 1.86 (s, 18H), 2.63 (s, 9H), 4.85(s, 2H), 7.28 (s, 6H), 7.77 (d, J=7.2 Hz, 2H), 8.18 (d, J=7.2 Hz, 2H),8.64 (s, 4H), 8.68 (d, J=4.4 Hz, 2H), 8.77 (d, J=4.4 Hz, 2H); LDMS obsd830.4, 751.5 [(M-Br)⁺]. FABMS obsd 832.3135; calcd 832.3141(C₅₄H₄₉BrN₄); λ_(abs)=420, 515, 547, 592, 649 nm; λ_(em) (λ_(ex)=515 nm)650, 720 nm.

5-[4-(Dimethoxyphosphorylmethyl)phenyl]-10,15,20-trimesitylporphyrin(27). A solution of 26 (200 mg, 240 μmol) in trimethylphosphite (2.2 mL)and toluene (5 mL) was heated to 120° C. under argon for 17 h. Thereaction mixture was cooled and concentrated under vacuum. The residuewas chromatographed [silica, CHCl₃→CHCl₃/ethyl acetate (95:5)] to afforda purple solid (164 mg, 79%): ¹H NMR δ-2.57 (br s, 2H), 1.84-1.85 (m,18H), 2.62 (s, 9H), 3.50 (d, J=21.6 Hz, 2H), 3.87 (d, J=11.1 Hz, 6H),7.27 (s, 6H), 7.67 (dd, J¹=8.4 Hz, J²=1.8 Hz, 2H), 8.15 (d, J=7.8 Hz,2H), 8.63 (s, 4H), 8.67 (d, J=4.8 Hz, 2H), 8.75 (d, J=4.8 Hz, 2H); ³¹PNMR δ 29.50; LDMS obsd 863.2; FABMS obsd 862.4045; calcd 862.4012(C₅₆H₅₅N₄O₃P); λ_(abs)=421, 514, 547, 593, 649 nm.

Zn(II)-5-[4-(Dimethoxyphosphorylmethyl)phenyl]-10,15,20-trimesitylporphyrin (Zn27). A solution of 27 (160 mg, 185μmol) in CHCl₃ (12 mL) was treated with a solution of Zn(OAc)₂.2H₂O (204mg, 0.929 mmol) in methanol (3 mL). Column chromatography [silica,CHCl₃/ethyl acetate (95:5)] afforded a purple solid (169 mg, 98%): ¹HNMR (THF-d₈) δ 1.85 (s, 18H), 2.60 (s, 9H), 3.47 (d, J=22.0 Hz, 2H),3.77 (d, J=11.1 Hz, 6H), 7.28 (s, 6H), 7.69 (d, J=7.5 Hz, 2H), 8.11 (d,J=7.6 Hz, 2H), 8.61-8.63 (in, 6H), 8.75 (d, J=4.5 Hz, 2H); ³¹P NMR δ29.2; LDMS obsd 926.1; FABMS obsd 924.3146; calcd 924.3147(C₅₆H₅₃N₄O₃PZn); λ_(abs)=423, 551, 592 nm.

4-(Diethoxyphosphorylmethyl)benzaldehyde (28). Triethylphosphite (9.28mL, 53.3 mmol) and α-bromo-p-toluic acid (10.4 g, 48.4 mmol) weresuspended in toluene (25 mL) and the mixture was heated to reflux for 18h. The mixture was cooled to room temperature. After 12 h, the resultingwhite solid was collected by suction filtration, washed with petroleumether and dried to yield 4-(diethoxyphosphorylmethyl)benzoic acid as awhite solid (10.2 g, 77%): mp 117-120° C.; ¹H NMR δ 1.26 (t, J=6.8 Hz,6H), 3.24 (d, J=25.6 Hz, 2H), 4.06 (m, 4H), 7.38-7.40 (m, 2H), 8.02 (d,J=7.6 Hz, 2H), 11.4 (br s, 1H); ¹³C NMR δ 16.5, 16.6, 33.4, 34.8, 62.8,62.9, 129.1, 129.2, 130.00, 130.05, 130.10, 130.48, 130.51, 137.3,137.4, 170.1; FABMS obsd 273.0896, calcd 273.0892; Anal. Calcd. forC₁₂H₁₇O₅P: C, 52.94; H, 6.29; Found: C, 52.92; H, 6.28. A suspension of4-(diethoxyphosphorylmethyl)benzoic acid (9.99 g, 36.7 mmol) inanhydrous THF (40 mL) at 0° C. was treated dropwise over 10 min withborane-THF complex (40.3 mL, 40.3 mmol, 1.0 M in THF). The reactionmixture was stirred at room temperature for 4 h. The reaction wasquenched by slow addition of water. The mixture was concentrated and theresidue was partitioned between water (100 mL) and CH₂Cl₂ (100 mL). Theaqueous layer was washed with CH₂Cl₂. The combined organic layers werewashed with water, dried (MgSO₄), and concentrated to give a yellow oil.Analysis by TLC and ¹H NMR spectroscopy showed starting material (˜10%)and the desired benzyl alcohol. The latter (9.56 g) was dissolved inCH₂Cl₂ and rapidly added to a sample of PCC (10.8 g, 50.1 mmol) inCH₂Cl₂ (50 mL) with rapid stirring. After 2 h, ethyl ether (150 mL) wasadded and the organic solution was decanted from the tarry residue. Theresidue was washed with ethyl ether (3×50 mL). The combined organicsolution was filtered through Florisil and concentrated to a brown oil.Kugelrohr distillation (190° C. @0.05 Torr) afforded a clear, colorlessoil (6.54 g, 77%): ¹H NMR δ 1.24 (t, J=7.2 Hz, 6H), 3.21 (d, J=22.4 Hz,2H), 4.03 (m, 4H), 7.45-7.48 (m, 2H), 7.83 (d, J=7.6 Hz, 2H), 9.99 (s,1H); ¹³C NMR δ 16.1, 16.2, 33.0, 34.9, 62.1, 62.2, 77.2, 129.49, 129.53,129.6, 129.66, 129.71, 130.2, 130.2, 138.8, 138.9, 191.61, 191.63; ³¹PNMR δ 25.4, 25.9; FABMS obsd 257.0949, calcd 257.0943 (C₁₂H₁₇PO₄).

5-[4-(Diethoxyphosphorylmethyl)phenyl]dipyrromethane (29). A solution of28 (2.00 g, 7.81 mmol) in pyrrole (22.0 mL, 315 mmol) was treated withTFA (60 μL, 780 μmol) at room temperature under argon for 5 min. TEA(109 μL, 782 μmol) was added and the reaction mixture was concentratedunder vacuum. Column chromatography (silica, ethyl acetate) afforded aviscous, yellow oil (1.33 g, 46%): ¹H NMR (CD₂Cl₂) δ 1.25 (t, J=6.4 Hz,6H), 3.11 (d, J=21.6 Hz, 2H), 4.01 (m, 4H), 5.43 (s, 1H), 5.86 (s, 2H),6.11 (d, J=2.8 Hz, 2H), 6.67 (s, 2H), 7.14 (d, J=8.0 Hz, 2H), 7.23 (d,J=8.0 Hz, 2H), 8.29 (br s, 2H); ¹³C NMR δ 16.6, 16.7, 32.5, 34.3, 43.74,43.75, 62.35, 62.44, 107.3, 108.3, 117.5, 128.8, 128.9, 130.06, 130.14,130.2, 132.81, 132.83, 141.39, 141.44; ³¹P NMR δ 27.6; FABMS obsd372.1598, calcd 372.1603 (C₂₀H₂₅N₂O₃P).

5-[4-(Diethoxyphosphorylmethyl)phenyl]-10,15,20-tri-p-tolylporphyrin(31). A solution of 30 (360 mg, 762 μmol) in dry THF/methanol [44 mL,(10:1)] was treated with NaBH₄ (576 mg, 15.2 mmol). After 40 min, thereaction mixture was poured into a stirred mixture of saturated aqueousNH₄Cl (150 mL) and CH₂Cl₂ (150 mL). The organic phase was washed withwater and brine, dried (Na₂SO₄), and concentrated. The resulting 30-diolwas dissolved in CH₂Cl₂ (305 mL). The solution was treated with 29 (284mg, 762 μmol) and InCl₃ (22 mg, 99 μmol) under argon for 1 h. DDQ (519mg, 2.29 mmol) was added and the mixture was stirred for 1 h at roomtemperature. TEA (1 mL) was added and the reaction mixture waschromatographed [silica, CHCl₃/ethyl acetate (9:1); silica, CHCl₃/ethylacetate (95:5)] to afford a purple solid. The solid was dissolved inCHCl₃ (120 mL) and treated overnight with a solution of Zn(OAc)₂.2H₂O(220 mg, 1.00 mmol) in methanol (12 mL) at room temperature. Thereaction mixture was concentrated and chromatographed [silica,CHCl₃/ethyl acetate (4:1)] to afford a purple solid (95 mg). Thiscompound could not be analyzed for purity due to its poor solubility.The solid was suspended (95 mg, 110 μmol) in CH₂Cl₂ (80 mL) and treatedwith TFA (420 μL, 5.5 mmol, 50 eq) at room temperature under argon for 1h. The solution was washed with 10% aqueous NaHCO₃ and water. Theorganic layer was dried (Na₂SO₄), filtered, and concentrated. Columnchromatography [silica, CHCl₃/ethyl acetate (1:1)] afforded a purplesolid (82 mg, 12%): ¹H NMR δ-2.78 (br s, 2H), 1.41 (t, J=6.9 Hz, 6H),2.71 (s, 9H), 3.50 (d, J=21.6 Hz, 2H), 4.22 (p, J=6.9 Hz, 4H), 7.55 (d,J=7.8 Hz, 6H), 7.69 (d, J=7.2 Hz, 2H), 8.10 (d, J=7.8 Hz, 6H), 8.16 (d,J=7.2 Hz, 2H), 8.80-8.86 (m, 8H); ³¹P NMR δ 27.1; LDMS obsd 805.2; FABMSobsd 806.3401, calcd 806.3386 (C₅₂H₄₇N₄O₃P); λ_(abs)=421, 516, 551, 593,649 nm.

5-(6-Bromohexyl)-10,15,20-tri-p-tolylporphyrin (33). A solution of 30(236 mg, 0.500 mmol) in dry THF/CH₃OH [22 mL, (10:1)] was treated withNaBH₄ (378 mg, 10.0 mmol). After 40 min, the reaction mixture was pouredinto a stirred mixture of aqueous NH₄Cl (100 mL) and CH₂Cl₂ (100 mL).The organic phase was isolated, washed with water, dried (Na₂SO₄), andconcentrated. The resulting 30-diol was dissolved in CH₂Cl₂ (200 mL).The solution was treated with 32 (153 mg, 0.500 mmol) and InCl₃ (14.2mg, 63.7 μmol) under argon for 40 min. DDQ (341 mg, 1.50 mmol) was addedand the mixture was stirred at room temperature for 1 h. TEA (3 mL) wasadded and the mixture was concentrated and filtered [silica,hexanes/CH₂Cl₂ (7:3)]. The porphyrin band was collected andrecrystallized (CH₂Cl₂/CH₃OH) to afford a purple solid (88 mg, 24%): ¹HNMR δ-2.72 (s, 2H), 1.60-1.70 (m, 2H), 1.75-1.84 (m, 2H), 1.85-1.96 (m,2H), 2.52-2.62 (m, 2H), 2.71 (s, 3H), 2.73 (s, 6H), 3.38-3.44 (m, 2H),5.00-5.07 (m, 2H), 7.52-7.59 (m, 6H), 8.05-8.12 (m, 6H), 8.82 (s, 4H),8.95 (d, J=5.1 2H), 9.47 (d, J=5.1 Hz, 2H); LDMS obsd 743.8; FABMS obsd742.2653, calcd 742.2671 (C₄₇H₄₃BrN₄); λ_(abs)=418, 516, 550, 594, 651nm.

Zn(II)-5-(6-Bromohexyl)-5,10,15-tri-p-tolylporphyrin (Zn33). A solutionof 33 (74.4 mg, 0.100 mmol) in THF/CH₂Cl₂[20 mL, (1:1)] was treated withZn(OAc)₂.2H₂O (109 mg, 0.500 mmol). After 1 h, the mixture wasconcentrated and chromatographed [silica, hexanes/toluene (1:1)] toafford a purple solid (81 mg, 85%): ¹H NMR δ 1.60-1.70 (m, 2H),1.80-1.96 (m, 4H), 2.52-2.62 (m, 2H), 2.67 (s, 3H), 2.70 (s, 6H), 3.45(t, J=6.8 Hz, 2H), 5.10-5.18 (m, 2H), 7.50-7.58 (m, 6H), 8.01-8.08 (m,6H), 8.76-8.80 (m, 4H), 8.91 (d, J=4.8 Hz, 2H), 9.60 (d, J=4.8 Hz, 2H);LDMS obsd 806.9; FABMS obsd 804.1825, calcd 804.1806 (C₄₇H₄₁BrN₄Zn);λ_(abs) 424, 553, 591 nm.

Zn(II)-5-[6-(Diethoxyphosphoryl)hexyl]-10,15,20-tri-p-tolylporphyrin(Zn34). A solution of Zn33 (40.4 mg, 50.1 μmol) in triethylphosphite (2mL) was refluxed under argon for 2 d. The mixture was chromatographed[silica, CH₂Cl₂→CH₂Cl₂/THF (95:5)] and the second red fraction wascollected, affording a purple solid (42.1 mg, 100%): ¹H NMR δ 1.67 (t,J=7.0 Hz, 6H), 1.48-1.68 (m, 6H), 1.77-1.90 (m, 2H), 2.46-2.62 (m, 2H),2.67 (s, 3H), 2.70 (s, 6H), 3.80-3.96 (m, 4H), 5.10-5.18 (m, 2H),7.51-7.58 (m, 6H), 8.01-8.08 (m, 6H), 8.75-8.80 (m, 4H), 8.91 (d, J=4.8Hz, 2H), 9.60 (d, J=4.8 Hz, 2H); ³¹P NMR δ 31.9; LDMS obsd 864.9; FABMSobsd 862.3003, calcd 862.2990 (C₅₁H₅₁N₄O₃PZn); λ_(abs)=424, 558, 599 nm.

Zn(II)-5-[6-(Dihydroxyphosphoryl)hexyl]-10,15,20-tri-p-tolylporphyrin(Zn35). A solution of Zn34 (43.2 mg, 50.0 μmol) in CHCl₃ (15 mL) wastreated with TEA (140 μL, 1.0 mmol) followed by TMS-Br (99.0 μL, 0.75mmol). The mixture was stirred overnight at 60-65° C. under argon. Thereaction mixture was cooled and water and CH₂Cl₂ were added. The organiclayer was separated, washed with water, dried (Na₂SO₄) and concentrated.Recrystallization (CH₂Cl₂/hexanes) afforded a purple solid (35.4 mg,88%): ¹H NMR δ 0.60-1.78 (br m, 4H), 2.16-2.36 (m, 4H), 2.40-2.50 (m,2H), 2.62 (s, 6H), 2.64 (s, 3H), 4.98-5.05 (m, 2H), 7.45-7.51 (m, 6H),7.98-8.03 (m, 6H), 8.75 (s, 4H), 8.83-8.87 (m, 2H), 9.49-9.53 (m, 2H);³¹P NMR δ 27.3; LDMS obsd 809.1; FABMS obsd 806.2392, calcd 806.2364(C₄₇H₄₃N₄O₃PZn); λ_(abs)=424, 558, 600 nm.

1-(4-Cyanophenyl)-1,1,1-tri-p-tolylmethane (37). A mixture of 36 (21.0g, 47.6 mmol) and CuCN (6.39 g, 71.4 mmol) in DMF (125 mL) was heated toreflux under argon for 18 h. The reaction mixture was cooled and pouredinto 500 mL of aqueous ammonia. Air was bubbled through the mixture for2 h. The mixture was filtered and the resulting solid was washed withwater until the washings were neutral (˜1 L). The solid was dissolved intoluene and the excess water was removed in a separatory funnel. Theorganic layer was dried (Na₂SO₄), filtered, and concentrated. Columnchromatography (silica, toluene, 7×25 cm) afforded a beige solid (11.1g, 60.0%): mp 207-209° C.; ¹H NMR δ 2.32 (s, 9H), 7.03-7.08 (m, 12H),7.36 (d, J=8.4 Hz, 2H), 7.52 (d, J=8.4 Hz, 2H); ¹³C NMR δ 20.9, 64.2,109.5, 119.0, 128.1, 128.2, 128.4, 128.7, 130.4, 130.7, 130.90, 130.94,131.2, 131.6, 135.8, 143.0, 152.9; FABMS obsd 388.2060, calcd 388.2065(M+H); Anal. Calcd for C₂₉H₂₅N: C, 89.89; H, 6.50; N, 3.61; Found: C,89.21; H, 6.60; N, 3.47.

1,1,1-Tris[4-(diethoxyphosphorylmethyl)phenyl]-1-(4-formylphenyl)methane(41). A solution of 37 (10.36 g, 26.7 mmol) in benzene (200 mL) washeated to reflux under argon. Then, samples of NBS (16.2 g, 90.9 mmol,3.3 eq) and AIBN (149 mg, 909 μmol) were added all at once. The mixturewas refluxed for 20 min then cooled. The mixture was filtered through asilica pad (7×10 cm, eluted with toluene) to remove succinimide. Removalof solvent afforded crude1,1,1-tris[4-(bromomethyl)phenyl]-1-(4-cyanophenyl)methane (38) as anoff-white solid (16.5 g). Analysis by ¹H NMR spectroscopy showed ˜10% oftolyl resonances, indicating incomplete bromination. A solution of crude38 (6.00 g, 9.61 mmol) in CH₂Cl₂/toluene [60 mL, (1:1)] at 0° C. wastreated dropwise with a solution of DIBALH (12.0 mL, 12.0 mmol, 1.0 Msolution in hexanes) under argon for 1 h. Then CHCl₃ (80 mL) and 2 N HCl(200 mL) were added and the mixture was stirred at room temperature for1 h. The organic layer was separated, washed with water, dried (Na₂SO₄),filtered and concentrated. Column chromatography (silica, CH₂Cl₂)afforded crude1,1,1-tris[4-(bromomethyl)phenyl]-1-(4-formylphenyl)methane (39) as awhite solid (4.93 g). A solution of crude 39 (4.79 g, 7.64 mmol) inCH₂Cl₂/methanol [80 mL, (1:1)] was treated with a solution of TiCl₄ (153μL, 153 μmol, 1.0 M in CH₂Cl₂) at room temperature under argon for 30min. TEA (153 μL) was added. After 30 min, water (50 mL) was added. Theorganic phase was extracted with ethyl ether (2×100 mL). The organiclayer was dried (Na₂SO₄), filtered, and concentrated to give crude1,1,1-tris[4-(bromomethyl)phenyl]-1-[4-(1,1-dimethoxymethyl)phenyl]methane(40) as an off-white solid (4.51 g). A mixture of crude 40 (4.51 g, 6.70mmol) in triethylphosphite (50 mL) was stirred under argon at 100° C.for 6 h. The solution was cooled and poured into 1 N HCl (250 mL). Themixture was extracted with ethyl acetate (150 mL). The layers wereseparated and the aqueous layer was washed with ethyl acetate (2×50 mL).The organic layers were combined, washed with 5% NaHCO₃ and water. Theorganic layer was dried (Na₂SO₄), filtered, and concentrated. Columnchromatography [silica, ethyl acetate/methanol (9:1)→(8:2)] afforded thetitle compound as a pale yellow oil (2.89 g, 54%): ¹H NMR δ 1.21 (t,J=6.8 Hz, 18H), 3.11 (d, J=22.4 Hz, 6H), 4.00 (m, 12H), 7.10 (d, J=8.4Hz, 6H), 7.18 (d, J=8.4 Hz, 6H), 7.36 (d, J=8.4 Hz, 2H), 7.73 (d, J=8.4Hz, 2H), 9.98 (s, 1H); ¹³C NMR δ 16.2, 16.3, 32.5, 33.8, 62.0, 62.1,125.7, 128.9, 129.0, 129.1, 129.2, 129.6, 129.7, 130.8, 130.9, 131.0,131.1, 131.4, 134.1, 144.4, 153.6, 191.8; ³¹P NMR δ 27.0; FABMS obsd799.2968, calcd 799.2930 (M+H) (C₄₁H₅₃O₁₀P₃).

5-[4-[1,1,1-Tris[4-(diethoxyphosphorylmethyl)phenyl]methyl]phenyl]dipyrromethane(42). A solution of 41 (2.83 g, 3.54 mmol) in pyrrole (24.7 mL, 354mmol) was degassed with argon for 10 min. A sample of InCl₃ (78 mg,0.354 mmol) was added and the mixture was stirred at room temperaturefor 90 min. Powdered NaOH (425 mg) was added and the mixture was stirredfor 30 min. The mixture was filtered and the pyrrole was removed undervacuum. Column chromatography [silica, ethyl acetate/MeOH (3:1)]afforded a pale yellow foam (2.50 g, 77%): mp 58-61° C.; ¹H NMR δ 1.21(t, J=6.8 Hz, 18H), 3.10 (d, J=21.6 Hz, 6H), 3.99 (m, 12H), 5.44, (s,1H), 5.89 (br s, 2H), 6.13 (m, 2H), 6.67 (m, 2H), 7.06-7.17 (m, 16H),8.10 (br s, 2H); ¹³C NMR δ 16.1, 16.2, 32.3, 33.7, 43.2, 62.0, 62.1,63.7, 106.9, 107.9, 117.1, 127.3, 128.77, 128.84, 128.9, 129.0, 130.8,130.95, 130.98, 132.4, 140.0, 144.8, 145.1, 145.2; ³¹P NMR δ 27.1; FABMSobsd 915.3679, calcd 915.3668 (M+H); Anal. Calcd for C₄₉H₆₁N₂O₉P₃: C,64.32; H, 6.72; O, 15.74; Found: C, 63.99; H, 6.64; O, 15.55.

5-(4-Ethynylphenyl)-1,9-bis(4-methylbenzoyl)dipyrromethane (43). Asolution of5-[4-(2-trimethylsilyl)ethynylphenyl)-1,9-bis(4-methylbenzoyl)dipyrromethane(2.00 g, 3.61 mmol) in CHCl₃ (75 mL) was treated with TBAF (4.33 mL,4.33 mmol, 1.0 M in THF) at room temperature under argon for 1 h. Thesolution was then washed with 10% aqueous NaHCO₃ and water. The organicphase was dried (Na₂SO₄), filtered and concentrated. Columnchromatography [silica, CH₂Cl₂/ethyl acetate (95:5)] afforded an orangefoam (1.37 g, 79%): mp 122-126° C.; ¹H NMR δ 2.39 (s, 6H), 3.10 (s, 1H),5.67 (s, 1H), 5.92 (m, 2H), 6.51 (m, 2H), 7.19 (d, J=8.0 Hz, 4H), 7.53(s, 4H), 7.66 (d, J=8.0 Hz, 4H), 11.64 (br s, 2H); ¹³C NMR δ 21.5, 44.9,77.3, 83.5, 111.2, 120.6, 121.0, 128.6, 128.9, 129.8, 131.2, 132.5,135.4, 140.3, 141.4, 142.2, 184.3; FABMS obsd 483.2059, calcd 483.2073[M+H]; Anal. Calcd for C₃₃H₂₆N₂O₂: C, 82.13; H, 5.43; Found: C, 81.54;H, 5.54.

Zn(II)-5-[4-[1,1,1-Tris[4-(diethoxyphosphorylmethyl)phenyl]methyl]phenyl]-10,15,20-tri-p-tolylporphyrin(Zn44). A solution of 30 (120 mg, 250 μmol) in dry THF/methanol [11 mL,(10:1)] was treated with NaBH₄ (190 mg, 5.10 mmol). After 40 min, thereaction mixture was poured into a stirred mixture of saturated aqueousNH₄Cl (150 mL) and CH₂Cl₂ (50 mL). The organic phase was washed withwater and brine, dried (Na₂SO₄), and concentrated. The resulting 30-diolwas dissolved in CH₂Cl₂ (100 mL) and treated with 42 (225 mg, 250 μmol)and InCl₃ (7.0 mg, 33 μmol) under argon for 1 h at room temperature. DDQ(170 mg, 750 μmol) was added. After 1 h, TEA (400 μL) was added. Columnchromatography [silica, ethyl acetate/methanol (9:1)] afforded a purplesolid (60 mg). The solid (60 mg, 0.045 mmol) was dissolved in CHCl₃ (30mL) and treated overnight with a solution of Zn(OAc)₂.2H₂O (60 mg, 0.27mmol) in methanol (5 mL). Column chromatography [silica, ethylacetate/methanol, (9:1)] afforded a purple solid (40 mg, 63%): ¹H NMR(THF-d₈) δ 1.15-1.18 (m, 18H), 2.68-2.69 (m, 9H), 3.10 (s, 3H), 3.16 (s,3H), 3.90-3.94 (m, 12H), 7.32-7.34 (m, 6H), 7.41-7.43 (m, 6H), 7.54-7.59(m, 8H), 8.05-8.09(m, 8H), 8.83-8.89 (m, 8H); ³¹P NMR δ 26.71; LDMS obsd1413.85; FABMS obsd 1410.4476, calcd 1410.4508; (C₈₁H₈₁N₄O₉P₃Zn);λ_(abs)=427, 558, 598 nm.

Zn(II)-5-[4-[1,1,1-Tris[4-(diethoxyphosphorylmethyl)phenyl]methyl]phenyl-15-(4-ethynylphenyl)-10,20-di-p-tolylporphyrin(Zn45). A solution of 43 (500 mg, 1.04 mmol) in THF/MeOH [38 mL, (10:1)]was treated with NaBH₄ (784 mg, 20.7 mmol). After 40 min, the reactionmixture was poured into a mixture of saturated aqueous NH₄Cl (100 mL)and CH₂Cl₂ (100 mL). The organic phase was collected, dried (Na₂SO₄),and concentrated to a yellow foam. The resulting 43-diol was dissolvedin CH₂Cl₂ (414 mL) and samples of 42 (950 mg, 1.04 mmol) and Yb(OTf)₃(822 mg, 1.33 mmol) were added. After 25 min, DDQ (705 mg, 3.12 mmol)was added followed by TEA (1 mL). After 30 min, the reaction mixture waschromatographed [silica, ethyl acetate/MeOH (8:2)] to recover thepartially purified free base porphyrin. The solid was dissolved in CHCl₃(60 mL) and treated with a solution of Zn(OAc)₂.2H₂O (228 mg, 1.04 mmol)in methanol (10 mL) for 12 h. Column chromatography [silica, ethylacetate/MeOH (9:1)→(8:2); silica, CHCl₃/MeOH (5:1)] afforded a purplesolid (335 mg, 24%): ¹H NMR δ 1.16 (t, J=7.2 Hz, 18H), 2.69 (s, 6H),3.12 (d, J=21.6 Hz, 6H), 3.77 (s, 1H), 3.90 (m, 12H), 7.30-7.33 (m, 6H),7.41 (d, J=8.0 Hz, 6H), 7.55-7.59 (m, 6H), 7.85 (d, J=8.0 Hz, 2H),8.06-8.10 (m, 6H), 8.17 (d, J=8.0 Hz, 2H), 8.81 (d, J=4.4 Hz, 2H),8.86-8.90 (m, 6H); ³¹P NMR δ 26.6; MALDI-MS (POPOP) 1424.9; FABMS obsd1420.4305, calcd 1420.4351 (C₈₂H₇₉N₄O₉P₃Zn); λ_(abs)=427, 555, 601 nm.

Zn(II)-5-[4-[1,1,1-Tris[4-(dihydroxyphosphorylmethyl)phenyl]methyl]phenyl]-10,15,20-tri-p-tolylporphyrin(Zn46). A solution of Zn44 (33 mg, 23.4 μmol) in CHCl₃ (2.3 mL) wastreated with TEA (65 μL, 470 μmol) and TMS-Br (46 μL, 350 μmol) and themixture was refluxed under argon. After 2 h, the solution was cooled andCHCl₃ (10 mL) and water (10 mL) were added. The porphyrin preferentiallydissolved in the aqueous layer. The mixture was concentrated. The solidwas suspended in hexanes, sonicated for 10 min, and centrifuged. Thesupernatant was decanted. This process was repeated once. The solid wasdissolved in methanol with sonication. The solution was poured intodiethyl ether and the precipitate was collected to afford a purple solid(24 mg, 82%): FABMS obsd 1242.2656, calcd 1242.2630 (C₆₉H₅₇N₄O₉P₃Zn);λ_(abs)=423, 522, 558, 599 nm.

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The foregoing is illustrative of the present invention, and is not to beconstrued as limiting thereof. The invention is defined by the followingclaims, with equivalents of the claims to be included therein.

1. A dipyrromethane selected from the group consisting of (a)1-phosphonoacyldipyrromethanes, and (b) 5-phosphono,1-acyldipyrromethanes.
 2. The compound of claim 1, wherein said5-phosphono is selected from the group consisting of dialkyl phosphono,diaryl phosphono, and dialkylaryl phosphono group.
 3. The compound ofclaim 1, wherein said compound is a 5-phosphono, 1-acyldipyrromethaneand said 1-acyl group is a 1-phosphonoacyl group.